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Sample records for helical ct scanning

  1. Helical CT scan for emergent patients with cerebrovascular diseases

    International Nuclear Information System (INIS)

    Matsumoto, Masato; Sato, Naoki; Nakano, Masayuki; Watanabe, Youichi; Kodama, Namio

    1995-01-01

    We studied 44 emergent patients with cerebrovascular diseases (18 cases of subarachnoid hemorrhage, 15 of occlusive lesions, 7 of intracerebral hematoma and 4 of suspected subarachnoid hemorrhage) using helical CT scan. The helical CT scan was performed with contrast medium at a rate of 3 ml/sec with a delay of 20 sec, and was carried out before conventional angiography. The reconstruction time of 3D-CTA was within 10 min. We were able to obtain findings for the lesion on 3D-CTA before those on conventional angiography. The 3D-CTA yielded excellent images of the vascular structures and anatomical relationships of the aneurysm, its neck and parent artery, and surrounding arteries. However, it proved difficult to visualize vessels of less than 1 mm in diameter, especially the perforating arteries. In occlusive diseases, the degree of stenosis depended on the changes in CT number threshold: at present, evaluations of the lesions should be made by conventional angiography. 3D-CTA using helical CT scan can thus be applied for emergent patients with cerebrovascular diseases. Surgical simulation images of 3D-CTA were especially useful at the time of operation. (author)

  2. Helical CT scan for emergent patients with cerebrovascular diseases

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    Matsumoto, Masato; Sato, Naoki; Nakano, Masayuki; Watanabe, Youichi; Kodama, Namio [Fukushima Medical Coll. (Japan)

    1995-08-01

    We studied 44 emergent patients with cerebrovascular diseases (18 cases of subarachnoid hemorrhage, 15 of occlusive lesions, 7 of intracerebral hematoma and 4 of suspected subarachnoid hemorrhage) using helical CT scan. The helical CT scan was performed with contrast medium at a rate of 3 ml/sec with a delay of 20 sec, and was carried out before conventional angiography. The reconstruction time of 3D-CTA was within 10 min. We were able to obtain findings for the lesion on 3D-CTA before those on conventional angiography. The 3D-CTA yielded excellent images of the vascular structures and anatomical relationships of the aneurysm, its neck and parent artery, and surrounding arteries. However, it proved difficult to visualize vessels of less than 1 mm in diameter, especially the perforating arteries. In occlusive diseases, the degree of stenosis depended on the changes in CT number threshold: at present, evaluations of the lesions should be made by conventional angiography. 3D-CTA using helical CT scan can thus be applied for emergent patients with cerebrovascular diseases. Surgical simulation images of 3D-CTA were especially useful at the time of operation. (author).

  3. Image quality of high-resolution CT with 16-channel multidetector-row CT. Comparison between helical scan and conventional step-shoot scan

    International Nuclear Information System (INIS)

    Sumikawa, Hiromitsu; Johkoh, Takeshi; Koyama, Mitsuhiro

    2005-01-01

    The aim of this study was to evaluate the image quality of high-resolution CT (HRCT) reconstructed from volumetric data with 16-channel multidetector-row CT (MDCT). Eleven autopsy lungs that were diagnosed histopathologically were scanned by 16-channel MDCT with the step-and-shoot scan mode and three helical scan modes. Each helical mode had each size of focal spot, pitch, and time of gantry rotation. HRCT images were reconstructed from the volumetric data with each helical mode and axial sequence data. Two observers evaluated the image quality and noted the most appropriate diagnosis for each imaging. Visualization of abnormal structures with one helical mode was equal to those with axial mode, whereas those with the other two helical modes were inferior to those with axial mode (Wilcoxon signed rank test; p<0.0001). There was no significant difference in diagnostic efficacy between modes. The image quality of HRCT with appropriate helical mode is equal to that with axial mode and diagnostic efficacy is equal among all modes. These results may indicate that sufficient HRCT images can be obtained by only one helical scan without the addition of conventional axial scans. (author)

  4. Comparison of radiation dose estimates, image noise, and scan duration in pediatric body imaging for volumetric and helical modes on 320-detector CT and helical mode on 64-detector CT

    International Nuclear Information System (INIS)

    Johnston, Jennifer H.; Podberesky, Daniel J.; Larson, David B.; Alsip, Christopher; Yoshizumi, Terry T.; Angel, Erin; Barelli, Alessandra; Toncheva, Greta; Egelhoff, John C.; Anderson-Evans, Colin; Nguyen, Giao B.; Frush, Donald P.; Salisbury, Shelia R.

    2013-01-01

    Advanced multidetector CT systems facilitate volumetric image acquisition, which offers theoretic dose savings over helical acquisition with shorter scan times. Compare effective dose (ED), scan duration and image noise using 320- and 64-detector CT scanners in various acquisition modes for clinical chest, abdomen and pelvis protocols. ED and scan durations were determined for 64-detector helical, 160-detector helical and volume modes under chest, abdomen and pelvis protocols on 320-detector CT with adaptive collimation and 64-detector helical mode on 64-detector CT without adaptive collimation in a phantom representing a 5-year-old child. Noise was measured as standard deviation of Hounsfield units. Compared to 64-detector helical CT, all acquisition modes on 320-detector CT resulted in lower ED and scan durations. Dose savings were greater for chest (27-46%) than abdomen/pelvis (18-28%) and chest/abdomen/pelvis imaging (8-14%). Noise was similar across scanning modes, although some protocols on 320-detector CT produced slightly higher noise. Dose savings can be achieved for chest, abdomen/pelvis and chest/abdomen/pelvis examinations on 320-detector CT compared to helical acquisition on 64-detector CT, with shorter scan durations. Although noise differences between some modes reached statistical significance, this is of doubtful diagnostic significance and will be studied further in a clinical setting. (orig.)

  5. Concept and development of measurement method of time sensitivity profile (TSP) in X-ray CT. Comparison of non-helical, single-slice helical, and multi-slice helical scans

    International Nuclear Information System (INIS)

    Tsujioka, Katsumi; Ida, Yoshihiro; Ohtsubo, Hironori; Takahashi, Yasukata; Niwa, Masayoshi

    2000-01-01

    We focused on the time element contained in a single CT image, and devised the concept of a time-sensitivity profile (TSP) describing how the time element is translated into an image. We calculated the data collection time range when the helical pitch is changed in non helical scans, single slice helical scans, and multi slice helical scans. We then calculated the time sensitivity profile (TSP) from the weighting applied when the data collection time range is translated into an image. TSP was also measured for each scanning method using our self-made moving phantom. TSPs obtained from the calculation and the experiments were very close. TSP showed interesting characteristics with each scanning method, especially in the case of multi slice helical scanning, in which TSP became shorter as helical pitch increased. We referred to the TSP's FWHM as the effective scanning time. When we conducted multi slice helical scanning at helical pitch 3, the effective scanning time increased to about 24% longer than that of a non helical scan. When we conducted multi slice helical scanning at helical pitch 5 or 6, the effective scanning time was about half that of a non helical scan. The time sensitivity profile (TSP) is a totally new concept that we consider an important element in discussing the time resolution of a CT scanner. The results of this review will provide significant data in determining the scanning parameters when scanning a moving object. (author)

  6. Dynamic helical CT mammography of breast cancer

    International Nuclear Information System (INIS)

    Yamamoto, Akira; Fukushima, Hitoshi; Okamura, Ryuji; Nakamura, Yoshiaki; Morimoto, Taisuke; Urata, Yoji; Mukaihara, Sumio; Hayakawa, Katsumi

    2006-01-01

    The purpose of this study was to determine whether dynamic helical computed tomography (CT)-mammography could assist in selecting the most appropriate surgical method in women with breast cancer. Preoperative contrast-enhanced helical CT scanning of the breast was performed on 133 female patients with suspicion of breast cancer at the same time as clinical, mammographic, and/or ultrasonographic examinations. The patients were scanned in the prone position with a specially designed CT-compatible device. A helical scan was made with rapid intravenous bolus injection (3 ml/s) of 100 ml of iodine contrast material. Three-dimensional maximum intensity projection (MIP) images were reconstructed, and CT findings were correlated with surgical and histopathological findings. Histopathological analysis revealed 84 malignant lesions and seven benign lesions. The sensitivity, specificity, and accuracy levels of the CT scanning were 94.6%, 58.6%, and 78.9%. Helical scanning alone revealed additional contralateral carcinomas in three of four patients and additional ipsilateral carcinomas in three of five patients. However, the technique gave false-positive readings in 24 patients. The preoperative CT-mammogram altered the surgical method in six patients. Dynamic helical CT-mammography in the prone position may be one of the choices of adjunct imaging in patients with suspected breast cancer scheduled for surgery. (author)

  7. Helical CT defecography

    International Nuclear Information System (INIS)

    Ferrando, R.; Fiorini, G.; Beghello, A.; Cicio, G.R.; Derchi, L.E.; Consigliere, M.; Resasco, M.; Tornago, S.

    1999-01-01

    The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus examined supine. Twenty-second helical scans were performed at rest and during evacuation; multiplanar reconstructions were obtained especially on the sagittal plane for comparison with conventional defecographic images. Coronal Helical CT defecography images permitted to map the perineal floor muscles, while sagittal reconstructions provided information on the ampulla and the levator ani. To conclude, Helical CT defecography performed well in study of pelvic floor disorders and can follow conventional defecography especially in questionable cases [it

  8. Acquiring 4D thoracic CT scans using a multislice helical method

    International Nuclear Information System (INIS)

    Keall, P J; Starkschall, G; Shukla, H; Forster, K M; Ortiz, V; Stevens, C W; Vedam, S S; George, R; Guerrero, T; Mohan, R

    2004-01-01

    Respiratory motion degrades anatomic position reproducibility during imaging, necessitates larger margins during radiotherapy planning and causes errors during radiation delivery. Computed tomography (CT) scans acquired synchronously with the respiratory signal can be used to reconstruct 4D CT scans, which can be employed for 4D treatment planning to explicitly account for respiratory motion. The aim of this research was to develop, test and clinically implement a method to acquire 4D thoracic CT scans using a multislice helical method. A commercial position-monitoring system used for respiratory-gated radiotherapy was interfaced with a third generation multislice scanner. 4D cardiac reconstruction methods were modified to allow 4D thoracic CT acquisition. The technique was tested on a phantom under different conditions: stationary, periodic motion and non-periodic motion. 4D CT was also implemented for a lung cancer patient with audio-visual breathing coaching. For all cases, 4D CT images were successfully acquired from eight discrete breathing phases, however, some limitations of the system in terms of respiration reproducibility and breathing period relative to scanner settings were evident. Lung mass for the 4D CT patient scan was reproducible to within 2.1% over the eight phases, though the lung volume changed by 20% between end inspiration and end expiration (870 cm 3 ). 4D CT can be used for 4D radiotherapy, respiration-gated radiotherapy, 'slow' CT acquisition and tumour motion studies

  9. Gynecological applications of helical CT using SmartPrep

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    Sakurada, Akira; Kakizaki, Dai; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    1999-11-01

    SmartPrep is software program for scanning a given region of interest (ROI) at optimal contrast density. An operator can arbitrarily define ROI and preset the CT value at which scanning should be started. After the injection of a contrast medium, system conducts continuous monitoring of the ROI and the operator starts helical scanning of the planned region when the present CT value has been reached. In comparison with conventional helical CT that requires a period of time from the beginning of contrast medium injection to the beginning of scanning, SmartPrep minimizes personal error and better depicts the artery-predominant phase under optimal conditions. In this study we examine the usefulness of contrast-enhanced helical CT using SmartPrep in the evaluation of gynecological disease. When the contrast medium was injected into the dorsal vein of the hand at a rate of 3 ml/sec, strong staining of pelvic arteries was observed in the CT images started at 17 to 23 sec after injection. The early-phase helical CT obtained under these conditions provided good depiction of lesions in cases of placenta accreta and invasive mole, as well as clear demonstration of tumor angiogenesis and evaluation of laterality in cases of cervical cancer. Comparison of the early and delayed phase also facilitated easier evaluation of lymph nodes than conventional comparison of simple and contrast-enhanced CT. The results thus suggest the usefulness of contrast-enhanced helical CT using SmartPrep in gynecology. (author)

  10. Clinical application of helical CT colonography

    International Nuclear Information System (INIS)

    Zeng Huiliang; Zhu Xinjin; Liang Rujian; Liang Jianhao; Ou Weiqian; Wen Haomao

    2009-01-01

    Objective: To investigate the clinical value of 16-slice helical CT colonography in the diagnosis of colon tumor and polypus. Methods: 16-slice helical CT volumetric scanning was performed in 18 patients with colonic disease, including colonic tumor (n=16) and colonic polypus (n=2). 3D images, virtual endoscopy and multiplanar reformation were obtained in the AW4.1 workstation. CT appearances were compared with operation and fiberoptic colonoscopy. Results: Satisfied results were achieved from 18 patients, no difference found in results between CT colonography and operation in 16 patients with colonic tumor. Conclusion: 16-slice helical CT colonography is of great value in preoperative staging of colonic tumor and have a high value in clinical application. (authors)

  11. Clinical Application of colored three-dimensional CT (3D-CT) for brain tumors using helical scanning CT (HES-CT)

    International Nuclear Information System (INIS)

    Ogura, Yuko; Katada, Kazuhiro; Fujisawa, Kazuhisa; Imai, Fumihiro; Kawase, Tsukasa; Kamei, Yoshifumi; Kanno, Tetsuo; Takeshita, Gen; Koga, Sukehiko

    1995-01-01

    We applied colored three-dimensional CT (colored 3D-CT) images to distinguish brain tumors from the surrounding vascular and bony structures using a work station system and helical scanning CT (HES-CT). CT scanners with a slip-ring system were employed (TCT-900S and X vigor). A slice thickness of 2 mm and bed speed of 2 mm/s were used. The volume of contrast medium injected was 60 to 70 ml. Four to 8 colors were used for the tissue segmentation on the workstation system (xtension) using the data transferred from HES-CT. Tissue segmentation succeeded on the colored 3D-CT images in all 13 cases. The relationship between the tumors and the surrounding structures were easily recognized. The technique was useful to simulate operative fields, because deep structures could be visualized by cutting and drilling the colored 3D-CT volumetric data. On the basis of our findings, we suggest that colored 3D-CT images should be used as a supplementary aid for preoperative simulation. (author)

  12. Three-dimensional-CT imaging of colorectal disease with thin collimation helical CT scanning

    International Nuclear Information System (INIS)

    Ogura, Toshihiro; Koizumi, Koichi; Sakai, Tatsuya; Kai, Shunkichi; Takatsu, Kazuaki; Maruyama, Masakazu

    1998-01-01

    We have conducted research on three-dimensional (3D)-CT-colonoscopy with thin collimation helical CT scanning over the past three years. This has lately become a subject of special interest. 3D-CT-colonoscopy has three kinds of visualizing methods depending on the threshold setting of CT values. The first one is the virtual endoscopy method which is displayed in a similar fashion to colonoscopic images. The second one is the air image method using the air in the digestive tract as a contrast medium. The third one is the pseudo-tract method which has characteristics of both virtual endoscopy and the air image method and visualizes in a shape of the digestive tract. The image visualized by 3D-CT-colonoscopy is similar to that of conventional colonoscopy and barium enema study, which is obtained with minimal invasion to patients. Obvious advanced carcinomas were easily visualized, and even a small flat polyp measuring 5 mm in size, was able to be observed retrospectively. The characteristics of our method are that we can easily make an examination in a short time and with little dependence on expert technique. Also patients have little discomfort compared to that experienced during colonoscopy and barium enema study. Important features are as follows; long calculation time, insufficient air insufflation, fecal material in the patient''s bowel, whole abdominal scan, and spatial resolution. In the near future, a multislice CT scanner system will have ability to overcome these problems. Therefore, 3D-CT-colonoscopy might be applied in the future for first line examination as a mass screening for colorectal carcinoma. (author)

  13. The quality of reconstructed 3D images in multidetector-row helical CT: experimental study involving scan parameters

    International Nuclear Information System (INIS)

    Shin, Ji Hoon; Lee, Ho Kyu; Choi, Choong Gon; Suh, Dae Chul; Lim, Tae Hwan; Kang, Weechang

    2002-01-01

    To determine which multidetector-row helical CT scanning technique provides the best-quality reconstructed 3D images, and to assess differences in image quality according to the levels of the scanning parameters used. Four objects with different surfaces and contours were scanned using multidetector-row helical CT at three detector-row collimations (1.25, 2.50, 5.00 mm), two pitches (3.0, 6.0), and three different degrees of overlap between the reconstructed slices (0%, 25%, 50%). Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering. The 72 images were graded on a scale from 1 (worst) to 5 (best) for each of four rating criteria, giving a mean score for each criterion and an overall mean score. Statistical analysis was used to assess differences in image quality according to scanning parameter levels. The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used. With regard to detector-row collimation and pitch, all levels of scanning parameters gave rise to significant differences, while in the degree of overlap of reconstructed slices, there were significant differences between overlap of 0% and of 50% in all levels of scanning parameters, and between overlap of 25% and of 50% in overall accuracy and overall mean score. Among the 18 scanning sequences, the highest score (4.94) was achieved with 1.25 mm detector-row collimation, 3.0 pitch, and 50% overlap between reconstructed slices. Comparison of the quality of reconstructed 3D images obtained using multidetector-row helical CT and various scanning techniques indicated that the 1.25 mm, 3.0, 50% scanning sequence was best. Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased

  14. A three-dimensional-weighted cone beam filtered backprojection (CB-FBP) algorithm for image reconstruction in volumetric CT-helical scanning

    International Nuclear Information System (INIS)

    Tang Xiangyang; Hsieh Jiang; Nilsen, Roy A; Dutta, Sandeep; Samsonov, Dmitry; Hagiwara, Akira

    2006-01-01

    Based on the structure of the original helical FDK algorithm, a three-dimensional (3D)-weighted cone beam filtered backprojection (CB-FBP) algorithm is proposed for image reconstruction in volumetric CT under helical source trajectory. In addition to its dependence on view and fan angles, the 3D weighting utilizes the cone angle dependency of a ray to improve reconstruction accuracy. The 3D weighting is ray-dependent and the underlying mechanism is to give a favourable weight to the ray with the smaller cone angle out of a pair of conjugate rays but an unfavourable weight to the ray with the larger cone angle out of the conjugate ray pair. The proposed 3D-weighted helical CB-FBP reconstruction algorithm is implemented in the cone-parallel geometry that can improve noise uniformity and image generation speed significantly. Under the cone-parallel geometry, the filtering is naturally carried out along the tangential direction of the helical source trajectory. By exploring the 3D weighting's dependence on cone angle, the proposed helical 3D-weighted CB-FBP reconstruction algorithm can provide significantly improved reconstruction accuracy at moderate cone angle and high helical pitches. The 3D-weighted CB-FBP algorithm is experimentally evaluated by computer-simulated phantoms and phantoms scanned by a diagnostic volumetric CT system with a detector dimension of 64 x 0.625 mm over various helical pitches. The computer simulation study shows that the 3D weighting enables the proposed algorithm to reach reconstruction accuracy comparable to that of exact CB reconstruction algorithms, such as the Katsevich algorithm, under a moderate cone angle (4 deg.) and various helical pitches. Meanwhile, the experimental evaluation using the phantoms scanned by a volumetric CT system shows that the spatial resolution along the z-direction and noise characteristics of the proposed 3D-weighted helical CB-FBP reconstruction algorithm are maintained very well in comparison to the FDK

  15. Clinical application of the helical CT in patients who are unable to hold their breath

    International Nuclear Information System (INIS)

    Toyama, Yoshihiro; Kimura, Naruhide; Ohkawa, Motoomi; Tanabe, Masatada.

    1997-01-01

    We performed helical CT in eighteen patients who were unable to hold their breath for 10 chest and 8 abdominal regions. Although there were respiratory artifacts in three cases, we could obtain the useful clinical information in all cases. In our experimental examinations, CT value of the phantom by helical scan was lower than that by conventional scan without movement of the phantom. With movement of it, the CT value was further lowered by either scan method, but the lowered rate was smaller by helical scan as the movement becomes faster. We consider that helical CT can be applied to patients who were unable to hold their breath. (author)

  16. New reconstruction algorithm in helical-volume CT

    International Nuclear Information System (INIS)

    Toki, Y.; Rifu, T.; Aradate, H.; Hirao, Y.; Ohyama, N.

    1990-01-01

    This paper reports on helical scanning that is an application of continuous scanning CT to acquire volume data in a short time for three-dimensional study. In a helical scan, the patient couch sustains movement during continuous-rotation scanning and then the acquired data is processed to synthesize a projection data set of vertical section by interpolation. But the synthesized section is not thin enough; also, the image may have artifacts caused by couch movement. A new reconstruction algorithm that helps resolve such problems has been developed and compared with the ordinary algorithm. The authors constructed a helical scan system based on TCT-900S, which can perform 1-second rotation continuously for 30 seconds. The authors measured section thickness using both algorithms on an AAPM phantom, and we also compared degree of artifacts on clinical data

  17. Non-contrast thin-section helical CT of urinary tract calculi in children

    International Nuclear Information System (INIS)

    Strouse, Peter J.; Bates, Gregory D.; Bloom, David A.; Goodsitt, Mitchell M.

    2002-01-01

    Background: Non-contrast thin-section helical CT has gained acceptance for the diagnosis of urinary tract calculi in adults, but experience with the technique in children is limited. Purpose: To evaluate the utility of non-contrast thin section helical CT for the diagnosis of urinary tract calculi in children. Materials and methods: Radiology databases at three pediatric institutions were searched to identify all pediatric patients evaluated by ''renal stone'' protocol CT scans (no oral or intravenous contrast, scans covering the entire urinary tract obtained in helical mode with narrow collimation (< 5 mm)). CT scans were reviewed for the primary finding of urinary tract calculi, for secondary signs of acute urinary tract obstruction and for evidence of alternative diagnoses. Medical records were reviewed to determine clinical presentation and to confirm the eventual diagnosis. Results: One hundred thirty-seven scans of 113 children (mean age: 11.2 years) were studied. Thirty-eight of 94 examinations (40%) performed on 82 children for acute pain and/or hematuria showed ureteral calculi. Alternative diagnoses were suggested by CT on 16 scans (17%). Twenty-eight scans were performed on 10 asymptomatic children with known calculus disease confirming renal stone burden on 21 scans (75%) and persistent ureteral calculi on 6 scans (21%). Upper tract calculi were demonstrated on 10 of 15 scans (67%) performed to evaluate for calculi in patients with known non-calculus genitourinary tract abnormalities. Conclusions: Non-contrast thin section helical CT is a useful method to diagnose urinary tract calculi in children. Radiation dose in this retrospective study may exceed the lowest possible radiation dose for diagnostic accuracy. Further research is needed to optimize CT imaging parameters, while maintaining diagnostic accuracy and minimizing radiation dose. (orig.)

  18. Experimental study of quantity to be taken as patient dose in helical multi-slice CT scan

    International Nuclear Information System (INIS)

    Liu Lantao; Wei Kedao; Yue Brorong; Wang Jianchao

    2009-01-01

    Objective: To bring forward a novel quantity which is used to be taken as effective dose in helical multi - slice CT scan and to validate it by experiment. Methods: Dot chamber and pencil-chamber were used to measure the doses which were performed under axial mode and helical multi-slice mode. Then the readings of doses were compared and analyzed. Results: The dose reading from dot chamber was close to the one from pencil - chamber under axial mode. The ratio is 1.14 for the readings from dot chamber under two scan modes and is 2.88 for the readings from pencil-chamber under two scan modes. Conclusions: The dose measured from dot chamber is an effective quantity to be taken as effective dose. However it is insufficient that the CTDI and DLP be used to be taken as effective dose as the limitation of pencil-chamber in length. (authors)

  19. Evaluation of the retrospective ECG-gated helical scan using half-second multi-slice CT. Motion phantom study for volumetry

    International Nuclear Information System (INIS)

    Yamamoto, Shuji; Matsumoto, Takashi; Nakanishi, Shohzoh; Hamada, Seiki; Takahei, Kazunari; Naito, Hiroaki; Ogata, Yuji

    2002-01-01

    ECG synchronized technique on multi-slice CT provide the thinner (less 2 mm slice thickness) and faster (0.5 sec/rotation) scan than that of the single detector CT and can acquire the coverage of the entire heart volume within one breath-hold. However, temporal resolution of multi-slice CT is insufficient on practical range of heart rate. The purpose of this study was to evaluate the accuracy of volumetry on cardiac function measurement in retrospective ECG-gated helical scan. We discussed the influence of the degradation of image quality and limitation of the heart rate in cardiac function measurement (volumetry) using motion phantom. (author)

  20. Adenocarcinoma of the pancreatic head: preoperative helical CT. Criteria of resectability

    International Nuclear Information System (INIS)

    Kozima, Shigeru; Szelagowski, Carlos; Tisserand, Guy L.; Ocampo, Carlos; Zandalazini, Hugo; Silva, Walter; Oria, Alejandro; Vidovic, Gustavo; Varas, Pablo

    2001-01-01

    Objective: The purpose of this study is to determine the accuracy of biphasic helical CT scanning in predicting resectability of adenocarcinoma of the head of the pancreas by staying tumor involvement of the portal and superior mesenteric veins. Material and methods: 46 patients with proven adenocarcinoma of the head of the pancreas who underwent curative or palliative surgery were studied with preoperative biphasic helical CT scanning. Tumor involvement of the portal and mesenteric veins was graduated on a 1-3 scale based on circumferential contiguity of the tumor vessel. Grade 1: without contact; grade 2: tumor involvement of less than 50% of the vessel; grade 3: tumor involvement of more than 50%. Results: The total number of vessels evaluated was 92. In our series the preoperative biphasic helical CT was accurate in 77% for resectability and unresectability. Conclusion: Our experience of staging in 3 grades with biphasic helical CT, vessel involvement the portal and superior mesenteric veins of adenocarcinoma of the head of the pancreas is highly specific for unresectable tumor in patients who were graded 2 and 3. (author)

  1. A rigid motion correction method for helical computed tomography (CT)

    International Nuclear Information System (INIS)

    Kim, J-H; Kyme, A; Fulton, R; Nuyts, J; Kuncic, Z

    2015-01-01

    We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed and the phantom. Motion correction was performed by restoring projection consistency using data from the motion tracking system, and reconstructing with an iterative fully 3D algorithm. Motion correction accuracy was evaluated by comparing reconstructed images with a stationary reference scan. We also investigated the effects on accuracy of tracker sampling rate, measurement jitter, interpolation of tracker measurements, and the synchronization of motion data and CT projections. After optimization of these aspects, motion corrected images corresponded remarkably closely to images of the stationary phantom with correlation and similarity coefficients both above 0.9. We performed a simulation study using volunteer head motion and found similarly that our method is capable of compensating effectively for realistic human head movements. To the best of our knowledge, this is the first practical demonstration of generalized rigid motion correction in helical CT. Its clinical value, which we have yet to explore, may be significant. For example it could reduce the necessity for repeat scans and resource-intensive anesthetic and sedation procedures in patient groups prone to motion, such as young children. It is not only applicable to dedicated CT imaging, but also to hybrid PET/CT and SPECT/CT, where it could also ensure an accurate CT image for lesion localization and attenuation correction of the functional image data. (paper)

  2. Helical CT of traumatic injuries of the thoracic aorta

    International Nuclear Information System (INIS)

    Mengozzi, E.; Burzi, M.; Miceli, M.; Lipparini, M.; Sartoni Galloni, S.

    2000-01-01

    Acute thoracic aortic injuries account for up to 10-20% of fatalities in high-speed deceleration road accidents and have an estimated immediate fatality rate of 80-90%. Untreated survivors to acute trauma (10-20%) have a dismal prognosis: 30% of them die within 6 hours, 40-50% die within 24 hours, and 90% within 4 months. It was investigated the diagnostic accuracy of Helical Computed Tomography (Helical CT) in acute traumatic injuries of the thoracic aorta, and the role of this technique in the diagnostic management of trauma patients with a strong suspicion of aortic rupture. It was compared retrospectively the chest Helical CT findings of 256 trauma patients examined June 1995 through August 1999. Chest Helical CT examinations were performed according to trauma score, to associated traumatic lesions and to plain chest radiographic findings. All the examinations were performed with no intravenous contrast agent administration and the pitch 2 technique. After a previous baseline study, contrast-enhanced scans were acquired with pitch 1 in 87 patients. Helical CT showed aortic lesions in 9 of 256 patients examined. In all the 9 cases it was found a mediastinal hematoma and all of them had positive plain chest radiographic findings of mediastinal enlargement. Moreover, in 6 cases aortic knob blurring was also evident on plain chest film and in 5 cases depressed left mainstem bronchus and trachea deviation rightwards were observed. All aortic lesions were identified on axial scans and located at the isthmus of level. Aortic rupture was always depicted as pseudo diverticulum of the proximal descending tract and intimal flap. It was also found that periaortic hematoma in 6 cases and intramural hematoma in 1 case. There were non false positive results in the series: 7 patients with Helical CT diagnosis of aortic rupture were submitted to conventional aortography that confirmed both type and extension of the lesions as detected by Helical CT, and all findings were

  3. Helical CT appearance of hypovascular small hepatocellular carcinoma with pathologic correlation

    International Nuclear Information System (INIS)

    Zheng Keguo; Xu Dasheng; Shen Jingxian

    2003-01-01

    Objective: To study the helical CT dual-phase enhancement manifestation of the hypodense small hepatocellular carcinoma, and to evaluate its correlation with the histopathology. Methods: The CT signs and its histopathologic changes were analyzed in 25 cases with 27 hypodense lesions in helical CT dual-phase enhancement. All the lesions were confirmed as small hepatocellular carcinoma by operation and histopathology. Results: (1) On unenhanced scan, 16 lesions were with obscure borders and 11 lesions were with well-delineated borders. On enhanced scan, only 7 lesions were with obscure borders and the other 20 lesions were with well-delineated borders, and their contours were slightly irregular. (2) On unenhanced scan, 18 lesions showed homogeneous hypodensity and 9 lesions showed heterogeneous hypodensity. On enhanced scan, only 6 lesions showed homogeneous hypodensity and the other 21 lesions showed heterogeneous hypodensity with multiple flecks of more hypodense areas. Conclusion: The helical CT dual-phase enhancement characteristic manifestations of hypodense small hepatocellular carcinoma were as follows: the border of the lesion was obscure on unenhanced scan, however the border of the lesion became well-delineated and slightly irregular, and there were multiple flecks of more hypodense areas in the lesions after enhancement. This might be an important character in distinguishing hypodense small hepatocellular carcinoma from other hypodense diseases in the liver

  4. Helical CT in evaluation of the bronchial tree

    International Nuclear Information System (INIS)

    Perhomaa, M.; Laehde, S.; Rossi, O.; Suramo, I.

    1997-01-01

    Purpose: To establish a protocol for and to assess the value of helical CT in the imaging of the bronchial tree. Material and Methods: Noncontrast helical CT was performed in 30 patients undergoing fiberoptic bronchoscopy for different reasons. Different protocols were compared; they included overlapping 10 mm, 5 mm, or 3 mm slices and non-tilted, cephalad or caudal tilted images. Ordinary cross-sectional and multiplanar 2D reformats were applied for visualization of the bronchial branches. The effect of increasing the helical pitch was tested in one patient. Results: A total of 92.1-100% of the segmental bronchi present in the helical acquisitions were identified by the different protocols. The collimation had no significant impact on the identification of the bronchial branches, but utilization of 3-mm overlapping slices made it easier to distinguish the nearby branches and provided better longitudinal visualization of the bronchi in 2D reformats. The tilted scans illustrated the disadvantage of not covering all segmental bronchi in one breath-hold. An increase of the pitch from 1 to 1.5 did not cause noticeable blurring of the images. CT and bronchoscopic findings correlated well in the area accessible to bronchoscopy, but CT detected 5 additional pathological lesions (including 2 cancers) in the peripheral lung. Conclusion: Helical CT supplemented with bronchography-like 2D reformats provides an effective method complementary to bronchoscopy in the examination of the bronchial tree. (orig.)

  5. Three-dimensional helical CT for treatment planning of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Hideko; Enomoto, Kohji; Ikeda, Tadashi [Keio Univ., Tokyo (Japan). School of Medicine] [and others

    1999-01-01

    The role of three-dimensional (3D) helical CT in the treatment planning of breast cancer was evaluated. Of 36 patients examined, 30 had invasive ductal carcinoma, three had invasive lobular carcinoma, one had DCIS, one had DCIS with minimal invasion, and 1 had Paget`s disease. Patients were examined in the supine position. The whole breast was scanned under about 25 seconds of breath-holding using helical CT (Proceed, Yokogawa Medical Systems, or High-speed Advantage, GE Medical Systems). 3D imaging was obtained with computer assistance (Advantage Windows, GE Medical Systems). Linear and/or spotty enhancement on helical CT was considered to suggest DCIS or intraductal spread in the area surrounding the invasive cancer. Of 36 patients, 24 showed linear and/or spotty enhancement on helical CT, and 22 of those 24 patients had DCIS or intraductal spread. In contrast, 12 of 36 patients were considered to have little or no intraductal spread on helical CT, and eight of the 12 patients had little or no intraductal spread on pathological examination. The sensitivity, specificity, and accuracy rates for detecting intraductal spread on MRI were 85%, 80%, and 83%, respectively. 3D helical CT was considered useful in detecting intraductal spread and planning surgery, however, a larger study using a precise correlation with pathology is necessary. (author)

  6. Dental-CT: image quality and absorbed radiation dose of different scan protocols

    International Nuclear Information System (INIS)

    Schorn, C.; Alamo, L.; Funke, M.; Grabbe, E.; Visser, H.; Hermann, K.P.

    1999-01-01

    Purpose: To develop a scan protocol for dental-CT which guarantees good image quality at the lowest possible radiation dose. Methods: In an experimental investigation Dental-CT (HSA, GE, Milwaukee, USA) of the mandible of two human skeletons positioned in a water tank were performed in order to define the most advantageous scan protocol. Tube currents ranged from 40 to 200 mA and the scan technique was modified (axial mode or helical mode with pitches of 1 to 3 and corresponding increments of 0.4 to 1.0 mm). 39 patients underwent a dental-CT with decreased current (80 mA) in the helical scan mode (pitch 2, slice thickness 1 mm). Dose measurements were performed for two different scan protocols (A: axial, 130 mAs, B: helical, 80 mA, pitch 2). Results: The preliminary investigations of image quality showed only a minor effect of the applied current. For the helical scan mode, pitches of more than 2 impaired image quality. A low increment had no advantages. There were no disadvantages in clinical practice using protocol B with decreased tube current. Absorbed radiation dose of dental CT performed with protocol B was decreased to one third in comparison to protocol A. Conclusions: A scan protocol with a low tube current (e.g., 80 mA, for a rotation time of 1 s) and a helical scan mode (e.g., for a slice thickness of 1 mm with a pitch of 2 and an increment of 1 mm) is recommended for performing dental-CT. (orig.) [de

  7. The evaluation of gallbladder contractibility for volume measurement by helical 3D-CT-cholangiography

    International Nuclear Information System (INIS)

    Hanaguri, Katsuro; Kimura, Hideaki; Kayashima, Yasuyo; Suemoto, Kouichiro; Makihata, Hiroshi; Maruhashi, Akira; Ohya, Toshihide; Ito, Katsuhide; Shen, Yun.

    1997-01-01

    As a new application of helical (spiral) scan, volume measurement has received a significant interest. Although it is important to evaluate gallbladder contractibility to decide on a treatment plan for a gallbladder lesion, qualitative analysis of gallbladder contractibility is very difficult owing to the fact that the volume of gallbladder can not be measured using usual DIC examination (plain X-P and tomography). In this study, the accuracy of volume measurement of helical CT was checked firstly by gallbladder phantom experiments. Then 128 cases of volume measurement of helical 3D CT Cholangiography (DIC-CT) were performed. Under the conditions of optimized scan technique (3 mm TH, 3 mm/s, 1 mm recon interval, Hispeed, GEMS), the difference of contractibility was obtained between clinical cases with and without thick wall. The experiment has shown that helical 3D CT volume measurement is very simple and highly accurate method which is useful for the evaluation of gallbladder contractibility. (author)

  8. Peripancreatic vascular abnormalities complicating acute pancreatitis: contrast-enhanced helical CT findings

    International Nuclear Information System (INIS)

    Mortele, Koenraad J.; Mergo, Patricia J.; Taylor, Helena M.; Wiesner, Walter; Cantisani, Vito; Ernst, Michael D.; Kalantari, Babak N.; Ros, Pablo R.

    2004-01-01

    Objective: To determine the prevalence and morphologic helical computed tomography (CT) features of peripancreatic vascular abnormalities in patients with acute pancreatic inflammatory disease in correlation with the severity of the pancreatitis. Materials and methods: One hundred and fifty-nine contrast-enhanced helical CT scans of 100 consecutive patients with acute pancreatitis were retrospectively and independently reviewed by three observers. CT scans were scored using the CT severity index (CTSI): pancreatitis was graded as mild (0-2 points), moderate (3-6 points), and severe (7-10 points). Interobserver agreement for both the CT severity index and the presence of peripancreatic vascular abnormalities was calculated (K-statistic). Correlation between the prevalence of complications and the degree of pancreatitis was estimated using Fisher's exact test. Results: The severity of pancreatitis was graded as mild (n=59 scans), moderate (n=82 scans), and severe (n=18 scans). Venous abnormalities detected included splenic vein (SV) thrombosis (31 scans, 19 patients), superior mesenteric vein (SMV) thrombosis (20 scans, 14 patients), and portal vein (PV) thrombosis (17 scans, 13 patients). Arterial hemorrhage occurred in five patients (6 scans). In our series, no cases of arterial pseudoaneurysm formation were detected. The interobserver agreement range for scoring the degree of pancreatitis and the overall presence of major vascular abnormalities was 75.5-79.2 and 86.2-98.8%, respectively. The presence of the vascular abnormalities in correlation with the severity of pancreatitis was variable. Conclusion: Vascular abnormalities are relatively common CT findings in association with acute pancreatitis. The CT severity index is insufficiently accurate in predicting some of these complications since no statistically significant correlation between their prevalence and the severity of pancreatitis could be established

  9. CT imaging before transcatheter aortic valve implantation (TAVI) using variable helical pitch scanning and its diagnostic performance for coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Shunsuke; Yamada, Yoshitake; Hashimoto, Masahiro; Okamura, Teppei; Jinzaki, Masahiro [Keio University School of Medicine, Department of Diagnostic Radiology, Shinanomachi, Shinjuku-ku, Tokyo (Japan); Yamada, Minoru [Keio University School of Medicine, Research Park, Tokyo (Japan); Yashima, Fumiaki; Hayashida, Kentaro; Fukuda, Keiichi [Keio University School of Medicine, Department of Cardiology, Tokyo (Japan)

    2017-05-15

    To evaluate the effectiveness of CT before TAVI using variable helical pitch (VHP) scanning and its diagnostic performance for coronary artery disease (CAD). Sixty patients (84.4 ± 4.6 years) scheduled for TAVI underwent CT using VHP scanning with the contrast material (CM) volume calculated as scanning time x weight [kg] x 0.06 mL. Retrospective electrocardiography (ECG)-gated scanning was utilized to examine the thorax, and non-ECG-gated scanning of the abdomen immediately followed. We analyzed CT attenuation values of the coronary arteries, aorta, iliac and femoral arteries. The coronary CT angiography images were evaluated for the presence of stenosis (≥50 %); invasive coronary angiography served as a reference standard. The average attenuations of all of the arteries were greater than 400 HU. We could evaluate the peripheral access vessels and dimensions of the ascending aorta, aortic root, and aortic annulus in all patients. The average volume of CM was 38.7 ± 8.5 mL. On per-patient and vessel analysis, CT showed 91.7 % and 89.5 % sensitivity, and 91.3 % and 97.4 % negative predictive value (NPV). CT using VHP scanning with an average CM volume of 38.7 mL is useful before TAVI and had a high sensitivity and NPV in excluding obstructive CAD. (orig.)

  10. Measurement of MV CT dose index for Hi-ART helical tomotherapy unit

    International Nuclear Information System (INIS)

    Wang Yunlai; Liao Xiongfei

    2010-01-01

    Objective: To evaluate the patient dose from Hi-ART MV helical CT imaging in image-guided radiotherapy. Methods: Weighted CT dose index (CTDI W ) was measured with PTW TM30009 CT ion chamber in head and body phantoms, respectively,for slice thicknesses of 2, 4, 6 mm with scanned range of 5 cm and 15 cm. Dose length products (DLP) were subsequently calculated. The CTDI W and DLP were compared with XVI kV CBCT and ACQSim simulator CT for routine clinical protocols. Results: An inverse relationship between CTDI and the slice thickness was found. The dose distribution was inhomogeneous owing to the attenuation of the couch. CTDI and DLP had close relationship with the slice thickness and the scanned range. Patient dose from MVCT was lower than XVI CBCT for head, but larger for body scan. Conclusions: CTDI W can be used to assess the patient dose in MV helical CT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA and QC program. Appropriate slice thickness and scan range should be chosen to reduce the patient dose. (authors)

  11. Thin section helical CT findings of klastskin tumor and benign stricture: cholangiographic correlation

    International Nuclear Information System (INIS)

    Choi, Guk Myeong; Han, Joon Koo; Kim, Tae Kyoung; Choi, Byung Ihn; Kim, Sun Whe; Cho, Yun Ku; Han, Man Chung; Yeon, Kyung Mo

    1997-01-01

    The purpose of this study was 1) to describe the thin section helical CT findings of hilar cholangiocarcinoma and of benign strcture, and to discuss the differential points between the two disease entities and 2) using cholangiographic correlation, to evaluate the diagnostic accuracy of helical CT in determining the extent of hilar cholangiocarcinoma. Twenty-seven patients with hilar cholangiocarcinoma and eight with benign biliary dilatation were studied. All except four with hilar cholangiocarcinoma, who underwentCT using a conventional scanner, were studied with two-phase helical CT. In all patients, cholangiographs were obtained by digital fluoroscopy after the injection of contrast materials into PTBD catheters. The level of obstruction was classified according to Bismuth, and 35 CT scans were studied blindly and retrospectively by two radiologists. The findings were analyzed for the presence of tumor, and then divided into two groups(cholangiocarcinomas and benign strictures), and the positive predictive value was calculated. The CT images of klatskin tumor were analyzed with special emphasis on the level and shape of the hilar obstruction. The level of biliary obstruction and extent of the tumor were carefully correlated with the results of cholangiography. Thin-section spiral CT correctly identified all tumor mass as a focal wall thickening obliterating the lumen. On arterial/portal phase CT scanning, 81% of infilterative tumors showed high attenuation. In all patients, differentiation between benign stricture and klaskin tumor was possible;correct identification of the level of obstruction and extent of tumor, according to Bismuth's classification, was possible in 63% of cases. For correct diagnosis of hilar cholangiocarcinoma and differentiation of benign stricture, helical CT was highly accurate and effective. Because of limital Z-axis resolution, however, the exact intraductal extent of the tumor was less accorately diagnosed.=20

  12. Preliminary study on helical CT algorithms for patient motion estimation and compensation

    International Nuclear Information System (INIS)

    Wang, G.; Vannier, M.W.

    1995-01-01

    Helical computed tomography (helical/spiral CT) has replaced conventional CT in many clinical applications. In current helical CT, a patient is assumed to be rigid and motionless during scanning and planar projection sets are produced from raw data via longitudinal interpolation. However, rigid patient motion is a problem in some cases (such as in the skull base and temporal bone imaging). Motion artifacts thus generated in reconstructed images can prevent accurate diagnosis. Modeling a uniform translational movement, the authors address how patient motion is ascertained and how it may be compensated. First, mismatch between adjacent fan-beam projections of the same orientation is determined via classical correlation, which is approximately proportional to the patient displacement projected onto an axis orthogonal to the central ray of the involved fan-beam. Then, the patient motion vector (the patient displacement per gantry rotation) is estimated from its projections using a least-square-root method. To suppress motion artifacts, adaptive interpolation algorithms are developed that synthesize full-scan and half-scan planar projection data sets, respectively. In the adaptive scheme, the interpolation is performed along inclined paths dependent upon the patient motion vector. The simulation results show that the patient motion vector can be accurately and reliably estimated using their correlation and least-square-root algorithm, patient motion artifacts can be effectively suppressed via adaptive interpolation, and adaptive half-scan interpolation is advantageous compared with its full-scale counterpart in terms of high contrast image resolution

  13. Pancreatic adenocarcinoma: dual-phase helical CT with surgical and histopathologic correlation

    International Nuclear Information System (INIS)

    Kim, Eun A; Yoon, Kwon Ha; Park, Seong Hoon; Yun, Ki Jung; Won, Jong Jin

    2003-01-01

    To determine the accuracy of dual-phase helical CT in assessing the resectability of pancreatic ductal adenocarcinoma, and to correlate the CT findings with the surgical and histopathologic findings. Thirty patients with pathologically proven cancer of the pancreas underwent arterial-and portal-phase helical CT scanning, and in the two of these, single-level dynamic CT was performed during celiac and superior mesenteric arteriography. In 17 patients who underwent surgery for potentially resectable cancer of the pancreatic head, tumor resectability was assessed. The CT findings were analyzed and correlated with these of surgery and histopathology. In 13 (76%) of the 17 patients who underwent surgery, tumors were resectable. Their average size was 2.76 cm (arterial phase), 2.30 cm (portal phase), and 2.48 cm (pathologically determined) and the overall accuracy of helical CT for assessing resectability was 87%. In all patients, the central portion of the tumors exhibited hypoattenuation at both phases; the peripheral portion showed hypoattenuation at the arterial phase and iso- (n=10) or hyperattenuation (n=3) at the portal phase. Single-level dynamic CT depicted a persistently hypoattenuating central portion and progressive and prolonged enhancement of the periphery. CT-histopathologic correlation showed that central hypoattenuation indicated the presence of tumor cells, necrosis (n=3) and mucin (n=4), while the peripheral iso- or hyperattenuated areas seen at the portal phase represented fibrosis and inflammatory infiltration. Histopathologic examination revealed tumoral infiltration of peripancreatic fat tissue (n=11) and microvascular invasion of major peripancreatic vessels (n=7). The dual-phase helical CT is useful in the determination of resectability in pancreas cancer and CT findings represent well the histopathologic features of pancreas cancer

  14. Pancreatic adenocarcinoma: dual-phase helical CT with surgical and histopathologic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun A; Yoon, Kwon Ha; Park, Seong Hoon; Yun, Ki Jung; Won, Jong Jin [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

    2003-03-01

    To determine the accuracy of dual-phase helical CT in assessing the resectability of pancreatic ductal adenocarcinoma, and to correlate the CT findings with the surgical and histopathologic findings. Thirty patients with pathologically proven cancer of the pancreas underwent arterial-and portal-phase helical CT scanning, and in the two of these, single-level dynamic CT was performed during celiac and superior mesenteric arteriography. In 17 patients who underwent surgery for potentially resectable cancer of the pancreatic head, tumor resectability was assessed. The CT findings were analyzed and correlated with these of surgery and histopathology. In 13 (76%) of the 17 patients who underwent surgery, tumors were resectable. Their average size was 2.76 cm (arterial phase), 2.30 cm (portal phase), and 2.48 cm (pathologically determined) and the overall accuracy of helical CT for assessing resectability was 87%. In all patients, the central portion of the tumors exhibited hypoattenuation at both phases; the peripheral portion showed hypoattenuation at the arterial phase and iso- (n=10) or hyperattenuation (n=3) at the portal phase. Single-level dynamic CT depicted a persistently hypoattenuating central portion and progressive and prolonged enhancement of the periphery. CT-histopathologic correlation showed that central hypoattenuation indicated the presence of tumor cells, necrosis (n=3) and mucin (n=4), while the peripheral iso- or hyperattenuated areas seen at the portal phase represented fibrosis and inflammatory infiltration. Histopathologic examination revealed tumoral infiltration of peripancreatic fat tissue (n=11) and microvascular invasion of major peripancreatic vessels (n=7). The dual-phase helical CT is useful in the determination of resectability in pancreas cancer and CT findings represent well the histopathologic features of pancreas cancer.

  15. A Study for Reappearance According to the Scan Type, the CT Scanning by a Moving Phantom

    International Nuclear Information System (INIS)

    Choi, Jae Hyock; Jeong, Do Hyeong; Choi, Gye Suk; Jang, Yo Jong; Kim, Jae Weon; Lee, Hui Seok

    2007-01-01

    CT scan shows that significant tumor movement occurs in lesions located in the proximity of the heart, diaphragm, and lung hilus. There are differences concerning three kinds of type to get images following the Scan type called Axial, Helical, Cine (4D-CT) mode, when the scanning by CT. To know how each protocol describe accurately, this paper is going to give you reappearance using the moving phantom. To reconstruct the movement of superior-inferior and anterior-posterior, the manufactured moving phantom and the motor following breathing were used. To distinguish movement from captured images by CT scanning, a localizer adhered to the marker on the motor. The moving phantom fixed the movement of superior-inferior upon 1.3 cm /1 min. The motor following breathing fixed the movement of anterior-posterior upon 0.2 cm /1 min. After fixing each movement, CT scanning was taken by following the CT protocols. The movement of A localizer and volume-reappearance analyzed by RTP machine. Total volume of a marker was 88.2 cm 3 considering movement of superior-inferior. Total volume was 184.3 cm 3 . Total volume according to each CT scan protocol were 135 cm 3 by axial mode, 164.9 cm 3 by helical mode, 181.7 cm 3 by cine (4D-CT) mode. The most closely describable protocol about moving reappearance was cine mode, the marker attached localizer as well. CT scan should reappear concerning a exact organ-description and target, when the moving organ is being scanned by three kinds of CT protocols. The cine (4D-CT) mode has the advantage of the most highly reconstructible ability of the three protocols in reappearance of the marker using a moving phantom. The marker on the phantom has always regular motion but breathing patients don't move like a phantom. Breathing education and devices setting patients were needed so that images reconstruct breathing as exactly as possible. Users should also consider that an amount of radiation to patients is being bombed.

  16. Low-dosage helical CT applications for chest medical checkup and lung cancer screening

    International Nuclear Information System (INIS)

    Wang Ping; Cui Fa; Liang Huanqing; Zheng Minfei

    2005-01-01

    Objective: A discussion on low-dosage helical CT applications on chest medical checkup and lung cancer screening. Methods: On the 100 chest medical check up with three different of protocols, including standard-dosage (the tube current was 230 mAs) were compared with low-dose (tube current was 50 mAs or 30 mAs). Results: Low-dosage helical CT scan provides excellent images. In 100 chest medical checkup, 39 nodules or masses were revealed, enlarged lymph node was noted in 1 case; emphysema or bullae was demonstrated in 3 segments; thickening of bronchial wall was shown in 2 cases; and localized pleural thickening was found in 1 case. Conclusion: In chest checkup or lung cancer screening low-dosage helical CT (tube current 30 mAs) will not only guarantee image quality but also reduce the radiation dose during the examination. (authors)

  17. Pitch dependence of longitudinal sampling and aliasing effects in multi-slice helical computed tomography (CT)

    International Nuclear Information System (INIS)

    La Riviere, Patrick J.; Pan Xiaochuan

    2002-01-01

    In this work, we investigate longitudinal sampling and aliasing effects in multi-slice helical CT. We demonstrate that longitudinal aliasing can be a significant, complicated, and potentially detrimental effect in multi-slice helical CT reconstructions. Multi-slice helical CT scans are generally undersampled longitudinally for all pitches of clinical interest, and the resulting aliasing effects are spatially variant. As in the single-slice case, aliasing is shown to be negligible at the isocentre for circularly symmetric objects due to a fortuitous aliasing cancellation phenomenon. However, away from the isocentre, aliasing effects can be significant, spatially variant, and highly pitch dependent. This implies that measures more sophisticated than isocentre slice sensitivity profiles are needed to characterize longitudinal properties of multi-slice helical CT systems. Such measures are particularly important in assessing the question of whether there are preferred pitches in helical CT. Previous analyses have generally focused only on isocentre sampling patterns, and our more global analysis leads to somewhat different conclusions than have been reached before, suggesting that pitches 3, 4, 5, and 6 are favourable, and that half-integer pitches are somewhat suboptimal. (author)

  18. Helical CT of ureteral disease

    International Nuclear Information System (INIS)

    Cikman, Pablo; Bengio, Ruben; Bulacio, Javier; Zirulnik, Esteban; Garimaldi, Jorge

    2000-01-01

    Among the new applications of helical CT is the study of the ureteral pathology. The objective of this paper was to evaluate patients with suspected pathology of this organ and the repercussion in the therapeutic plans. We studied 23 patients with a helical CT protocol, without IV contrast injection and performed multiplanar reconstruction (MPR). We called this procedure Pielo CT. Thirteen ureteral stones were detected, 6 calculi, 2 urinary tract tumors, dilatation of the system in a patient with neo-bladder. In 2 patients, in whom ureteral pathology was ruled out, we found other alterations that explained the symptoms, (gallbladder stones, disk protrusion). The Pielo CT let decide a therapeutical approach in 20 or 21 patients with ureteral pathology. (author)

  19. New approach to lung cancer screening with helical volume CT

    International Nuclear Information System (INIS)

    Midorikawa, S.; Hashimoto, N.; Katakura, T.; Suzuki, K.

    1990-01-01

    This paper evaluates the relationship between reducing radiation dose to the patient and maintaining the clinical quality of the chest image in lung cancer screening by helical-volume CT (HVCT). The authors evaluated the changing relationship between radiation dose and clinical quality after changing the HVCY scanning conditions (such as stroke of patient transport and section thickness) as well as adding copper filters of various thickness and using high-voltage x-ray examination to complement CT examinations. The authors were able to reduce radiation dose by changing the HVCT scanning conditions (eg, stroke of 20 mm/sec, with a section thickness of 10 mm)

  20. Dual phase helical CT: diagnosis value for early pancreatic carcinoma

    International Nuclear Information System (INIS)

    Shen Bingqi; Zhang Ling; Zheng Keguo; Xu Dasheng

    2006-01-01

    Objective: To study dual-phase helical CT for the evaluation of early pancreatic cacinoma. Methods: Dual-phase helical CT was performed on 21 patients with early pancreatic carcinoma. In the enhanced imaging the contrast material was intravenously injected in a dose of 1.5 ml/kg at a rate of 3 ml/s. The image acquisition of the lesion in pancreatic phase (PP) and portal venous phase (PVP) were started at 35 seconds and 65 seconds after the start of the injection respectively. The enhancement of normal pancreas and tumor during the two phases was observed and compared. All data were statistically analyzed. Results: Tumor-pancreas contrast was significantly greater in PP (45.16±113.23) HU than in PVP (23.15±12.44) HU (t=2.13, P<0.01). Conclusion: Dual-phase helical CT scan for pancreas, including the imaging of the pancreatic and portal , venous phase, can be applied as an optimal selection. It can delineate early pancreatic carcinoma clearly and provide more information for the diagnosis of the lesion. The tumor-pancreas contrast was much higher' in PP than in PVP. (authors)

  1. The detectability of hepatic metastases in candidates of radiofrequency ablation: comparison for helical CT scanning and late-phase pulse-inversion harmonic imaging

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    Lee, Kang Won; Yoon, Kwon Ha; Kim, Eun A; Park, Ki Han; Juhng, Seon Kwan; Won, Jong Jin [School of Medicine, Wonkwang Univ., Iksan (Korea, Republic of)

    2002-02-01

    To compare dual-phase helical CT and pulse inversion harmonic US using microbubble contrast agents in the detection of hepatic metastases prior to radiofrequency (RF) ablation. Twenty-one patients in whom hepatic metastases from colorectal cancer had been diagnosed by dual-phase CT scanning and who were considered to be candidates for RF ablation underwent pulse-inversion barmonic US examination. Images were obtained 5 minutes after the bolus injection of microbubble contrast agent SH U 508 A (4.0 g, 300 mg/mL). The number of metastatic tumors revealed by CT and US was determined, and the findings were statistically analysed. The influence of the results of US examination on treatment planning was also evaluated. In 21 patients, 48 metastaic lesions were detected by helical CT, and 56 lesions by US. These eight additional lesions revealed by US occurred in six patients (29%), and their diameter was 3-13 (mean, 7.2) mm. In three of these patients, RF ablation could not be performed ,while in the other three, the additional lesions were ablated. Pulse-inversion harmonic US imaging using microbubble contrast agents may depict small hepatic metastatic tumors that were not apparent at CT. US-therefore appears to be useful in the planning of treatment prior to the RF ablation of hepatic metastases.

  2. Clinical application of multi-slice helical CT volumetric scanning in lumber spine

    International Nuclear Information System (INIS)

    Wang Ling; Ge Yinghui; Zhu Shaocheng; Zhang Ming; Cheng Tianming; Lei Zhidan; Lv Chuanjian; Sun Xiaoping; Wu Minghui; Guo Ying; Ma Qianli; Wen Zeying

    2008-01-01

    Objective: To evaluate the clinical application value of multi-slice helical CT volumetric (VH) scanning in lumber spine. Methods: One thousand of patients with back and leg pain who underwent CT examinations were selected as subjects. We simulated the traditional protocol of single-slice(SS) discrete scanning for L3/4, L4/5, and L5/S1 intervertebral discs. The VH scanning mode was performed with 120 kV, 210 mAs, pitch of 1.5 and coverage of 97.5 mm. The simulated SS scanning mode was performed with 120 kV, 240 mAs and coverage of 45.0 mm. The diagnostic outcomes and the radiation doses were compared between the two scanning modes. Two groups doctors observed ten terms, including the osseous spinal stenosis, narrowed intervertebral space and so on in two scanning modes respectively. Then consistency analysis of the data was carded out. Results: The VH scanning mode showed far more features than the SS mode. The detection rates of the VH mode in the osseous spinal stenosis, narrowed intervertebral space, herniated nucleus pulposus, narrowed lateral recess, vertebral lesion, hypertrophy of L5 transverse process, abnormal direction of facet, facet degeneration, lumbar spondyloschisis, and paraspinal soft tissue were 11.8% (n=118), 38.5% (n=385), 9.3% (n=93), 46.8% (n=468), 31.4% (n=314), 5.7% (n= 57), 25.4% (n=254), 49.7% (n=497), 9.9% (n=99), and 0.6% (n=6) respectively, while the detection rates of the SS mode in ten terms were 5.6% (n=56), 0, 0.6% (n=6), 27.9% (n=279), 22.4% (n=224), 1.2% (n=12), 16.7% (n=167), 37.2% (n=372), 0.5% (n=5), and 0.2% (n=2) respectively. The difference between the two groups had statistically significance (average P 0.05). The detection rates of the VH mode were higher than the SS mode in the osseous spinal stenosis, narrowed intervertebral space, herniated nucleus pulposus, lumbar spondyloschisis, being 6.2% (n=62), 38.5% (n=385), 8.7% (n=87), and 9.4% (n=94), respectively. In addition, VH mode only partially showed the articular

  3. Three-dimensional image analysis of the skull using variable CT scanning protocols-effect of slice thickness on measurement in the three-dimensional CT images

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ho Gul; Kim, Kee Deog; Park, Hyok; Kim, Dong Ook; Jeong, Hai Jo; Kim, Hee Joung; Yoo, Sun Kook; Kim, Yong Oock; Park, Chang Seo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2004-07-15

    To evaluate the quantitative accuracy of three-dimensional (3D) images by mean of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0 (Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons' two-sample test. 11 line items in Conventional 3 mm, 8 in Helical 3 mm, 11 in Conventional 5 mm, 10 in Helical 5 mm, 5 in Conventional 7 mm and 9 in Helical 7 mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2 mm in 19 line items of Conventional 3 mm. 20 of Helical 3 mm, 15 of Conventional 5 mm, 18 of Helical 5 mm, 11 of Conventional 7 mm and 16 of Helical 7 mm. Considering image quality and patient's exposure time, scanning protocol of Helical 5 mm is recommended for 3D image analysis of the skull in CT.

  4. Experimental study of abdominal CT scanning exposal doses adjusted on the basis of pediatric abdominal perimeter

    International Nuclear Information System (INIS)

    Wei Wenzhou; Zhu Gongsheng; Zeng Lingyan; Yin Xianglin; Yang Fuwen; Liu Changsheng

    2006-01-01

    Objective: To optimize the abdominal helical CT scanning parameters in pediatric patients and to reduce its radiation hazards. Methods: 60 canines were evenly grouped into 4 groups on the basis of pediatric abdominal perimeter, scanned with 110,150,190 and 240 mAs, and their qualities of canine CT images were analyzed. 120 pediafric patients with clinic suspected abdominal diseases were divided into 4 groups on the basis of abdominal perimeter, scanned by optimal parameters and their image qualities were analyzed. Results: After CT exposure were reduced, the percentages of total A and B were 90.9 % and 92.0 % in experimental canines and in pediatric patients, respectively. Compared with conventional CT scanning, the exposure and single slice CT dose index weighted (CTDIw) were reduced to 45.8%-79.17%. Conclusion: By adjusted the pediatric helical CT parameters basedon the of pediatric abdominal perimeter, exposure of patient to the hazards of radiation is reduced. (authors)

  5. Identification of the segmental artery feeding the anterior spinal artery. Correlation between helical CT and angiography

    International Nuclear Information System (INIS)

    Nishimura, Jun-ichi; Lee, Jin; Koike, Shigeomi

    2005-01-01

    We investigated whether identification of the segmental artery feeding the anterior spinal artery (ASA) is possible by single-slice helical CT. Enhanced CT and angiography were performed in 14 patients with retroperitoneal, liver, or bone tumor. A single-slice helical CT scanner with 7 mm collimation and a 1.0 helical pitch was used. Scanning was started 25 to 30 sec after an intravenous injection of 100 ml of contrast medium at a rate of 3.0 ml/sec. We predicted the segmental artery feeding the ASA in all 14 patients using enhanced CT images. In 12 of the 14 patients, the segmental artery feeding the ASA was angiographically identified. In 7 of these 12 patients, the level of the segmental artery feeding the ASA identified on segmental arteriogram was the same level as that predicted by enhanced CT. In the remaining 5 patients, the level of the segmental artery feeding the ASA identified on segmental arteriogram was one level higher or lower than the predicted spinal level. We could identify the segmental artery feeding the ASA by detailed examination and interpretation of single-slice helical CT images. (author)

  6. Helical CT for secondary screening of lung cancer

    International Nuclear Information System (INIS)

    Mori, Kiyoshi; Onishi, Tsukasa; Tominaga, Keigo; Kishiro, Izumi; Yokoyama, Kohki.

    1995-01-01

    Helical CT was used on a trial basis for secondary screening of lung cancer, and its clinical usefulness is discussed in this report. The subjects of 157 patients with abnormal shadows on plain chest X-ray images were chosen between November 1993 and August 1994. Imaging parameters used for screening CT were as follows: 50 mA, 120 kV, a couch-top movement speed of 20 mm/s, and a beam width of 10 mm. The entire lung field was scanned during a single breath-hold. Reconstructed images were generated at 10-mm intervals by the 180deg interpolation method, and films were produced. Images of the entire lung field were made during a single breath-hold in all patients. Abnormal shadows were detected in 73 of 157 patients by screening CT. These 73 patients included 14 with lung cancer, 53 with benign lesions, one under observation, and five others. The average diameter of the tumors was 11.1 mm. The lung cancers detected all arose in the periphery, and were classified into stage I (10 patients), stage IIIA (3 patients), and stage IV with bone metastases (1 patient). Lung cancers in clinical stage I (3 patients) and stage IV (1 patient) were difficult to see on plain chest X-ray films. We conclude that screening CT is useful for early diagnosis of lung cancer because the entire lung field can be imaged during a single breath-hold. Therefore, helical CT can be expected to be useful in screening for lung cancer. (author)

  7. Scanning technology with multi-slice helical CT in security inspection domain

    International Nuclear Information System (INIS)

    Wang Jue; Wang Fuquan; Jiang Zenghui

    2008-01-01

    The paper analyzes the technology conditions of security inspection in home and abroad, and expatiates technology of spiral CT and how to define CT value etc, with studying on the key technology of spiral CT scanning way (X-RAY, detector, technology of pulley etc) and mutual relation. By comparing the present products of security inspection, the conclusion was drawn that it is inevitable to develop the tendency of security inspection area with the checking and discerning the substance by using the technology of multi-layer spiral CT. (authors)

  8. Helical CT in acute lower gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Ernst, Olivier; Leroy, Christophe; Sergent, Geraldine; Bulois, Philippe; Saint-Drenant, Sophie; Paris, Jean-Claude

    2003-01-01

    The purpose of this study was to assess the usefulness of helical CT in depicting the location of acute lower gastrointestinal bleeding. A three-phase helical CT of the abdomen was performed in 24 patients referred for acute lower gastrointestinal bleeding. The diagnosis of the bleeding site was established by CT when there was at least one of the following criteria: spontaneous hyperdensity of the peribowel fat; contrast enhancement of the bowel wall; vascular extravasation of the contrast medium; thickening of the bowel wall; polyp or tumor; or vascular dilation. Diverticula alone were not enough to locate the bleeding site. The results of CT were compared with the diagnosis obtained by colonoscopy, enteroscopy, or surgery. A definite diagnosis was made in 19 patients. The bleeding site was located in the small bowel in 5 patients and the colon in 14 patients. The CT correctly located 4 small bowel hemorrhages and 11 colonic hemorrhages. Diagnosis of the primary lesion responsible for the bleeding was made in 10 patients. Our results suggest that helical CT could be a good diagnostic tool in acute lower gastrointestinal bleeding to help the physician to diagnose the bleeding site. (orig.)

  9. An evaluation of the regional cerebral blood flow (rCBF) measurement by xenon-enhanced dynamic CT with helical scanning technique and the functional imaging by multiplanar reconstruction (MPR). Fundamental study and clinical application

    International Nuclear Information System (INIS)

    Watanabe, Kenichi

    1997-01-01

    We evaluated the quantitative rCBF by xenon-enhanced dynamic CT with helical scanning technique on all brain regions, and also examined clinical usefulness of coronal and sagittal section images which are similar to SPECT images obtained by the functional multiplanar reconstitution (MPR) imaging of many successive flow maps. We used 14 clinical cases. The conventional xenon-enhanced CT was simple and ideal method to measure rCBF, however, it had disadvantages; it gives a few laminagraphical images or only the axial directional images, compared to SPECT or PET. There is a risk to overlook lesions out of the image or not to obtain the whole images of the lesion. Although the helical scanning technique has a methodological characteristics to use adjacent data for the image reconstitution, it is by no means inferior to the conventional method in the contrast resolution or the image resolution when the co-helical function and an appropriate reconstituted function were used. It has an advantage to scan all brain regions by only one cycle of scanning. Furthermore on making good use of the property that the helical scanning technique can give the successive data, we can observe rCBF by coronal and sagittal images when many flow maps were made up by reconstituted images of the narrow steps. This shows the clinical usefulness of this technique. One of the future problem to be solved is to decrease the exposure dose. (K.H.)

  10. Utility of three-dimensional helical CT in the diagnosis of breast cancer

    International Nuclear Information System (INIS)

    Maeda, Yoshiaki; Hata, Yoshinobu; Matsuoka, Shinnichi; Nakajima, Nobuhisa; Ito, Toichi; Osada, Tadahiro; Sano, Fumio

    2004-01-01

    Although utility of three-dimensional (3D) helical CT for preoperative examination of breast cancer has been discussed, the accuracy of the helical CT in diagnosing breast cancer has not been fully evaluated. In this study 56 malignant and 28 benign breast tumors were evaluated preoperatively with 3D-helical CT, and their imaging results were compared with pathological findings of surgical specimens. Helical CT identified the presence of malignancy in 54 out of the 56 cancer cases tested and the sensitivity and specificity in distinguishing between malignant and benign tumors were 82% and 57%, respectively. The sensitivity and specificity in diagnosing the presence of metastatic axillary lymph nodes using helical CT were 70% and 80%, respectively. The sensitivity and specificity in diagnosing the presence of extensive intraductal component (EIC) using helical CT were 71% and 86%, respectively. Helical CT visualized all of the tumors in multifocal breast cancer cases. In conclusion, 3D-helical CT is a useful modality for preoperative examination of breast cancer, especially for assessing axillary lymph node status, and EIC, and will be helpful for conducting sentinel lymph node biopsy (SNLB) and breast-conserving surgery. (author)

  11. Multislice helical CT (MSCT) for mid-facial trauma: optimization of parameters for scanning and reconstruction

    International Nuclear Information System (INIS)

    Dammert, S.; Funke, M.; Obernauer, S.; Grabbe, E.; Merten, H.A.

    2002-01-01

    Purpose: To determine the optimal scan parameters in multislice helical CT (MSCT) of the facial bone complex for both axial scanning and multiplanar reconstructions. Material and Methods: An anthropomorphic skull phantom was examined with a MSCT. Axial scans were performed with continuously increasing collimations (4 x 1.25 - 4 x 2.5 mm), tube current (20 - 200 mA) and table speeds (3.75 mm/rot. and 7.5 mm/rot.). Multiplanar reconstructions in coronal and parasagittal planes with different reconstruction increment and slice thickness were evaluated in terms of image noise, contour artifacts and visualisation of anatomical structures. Results: The best image quality was obtained with a collimation of 4 x 1.25 mm and a - table speed of 3.75 mm/rot. A reconstruction increment of 0.6 mm achieved the best time to image quality relation. With these parameters the bone structures were depicted in an optimal way without artifacts. The tube current could be reduced to 50 mA without significant loss of image quality. The optimized protocol was used for regular routine examinations in patients with facial trauma (n = 66). Conclusions: Low-dose MSCT using thin collimation, low table speed and small reconstruction increments provides excellent data for both axial images and multiplanar reconstructions in patients with facial trauma. An additional examination in coronal orientation is therefore no longer necessary. (orig.) [de

  12. COMPUTED TOMOGRAPHY DOSE INDEX MEASUREMENT FOR Hi-ART MEGAVOLTAGE HELICAL CT.

    Science.gov (United States)

    Liu, Minglu; Wang, Yunlai; Liao, Xiongfei

    2016-11-01

    On-line megavoltage computed tomography (MVCT) images are used to verify patient daily set-up in Hi-ART helical TomoTherapy unit. To evaluate the patient dose from MVCT scanning in image guidance, weighted computed tomography (CT) dose index (CTDI w ) was measured with PTW TM30009 CT pencil chamber in head and body phantoms for slice thicknesses of 2, 4 and 6 mm with different scan lengths. Dose length products (DLPs) were subsequently calculated. The CTDI w and DLP were compared with XVI kV CBCT and Brilliance simulator CT for routine clinical protocols. It was shown that CTDI and DLP had close relationship with the slice thickness and the scan length. The dose distribution in the transversal plane was very inhomogeneous due to the attenuation of the couch. Patient dose from MVCT was lower than XVI CBCT for the head scan, while larger for body scan. CTDI w , which is measured easily and reproducibly, can be used to assess the patient dose in MVCT. Regular measurement should be performed in QA & QC programmes. Appropriate slice thickness and scan range should be chosen to reduce the patient dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Usefulness of 3D-image of ossicles with helical scanning

    International Nuclear Information System (INIS)

    Makihata, Hiroshi; Kimura, Hideaki; Hanaguri, Katsurou; Fukushima, Noriyuki; Oda, Yukari

    1995-01-01

    It is important to understand the abnormalities of ossicles (continuity, destruction and malformation) in clinical practice of middle ear diseases. Multidirection exposures were needed to visualize ossicles with the conventional CT scanning, because they are visualized in 2D images. It was difficult to make patients hold the posture and to settle the problems such as an increase in X-ray dose. We created 3D images of ossicles with a helical scanning, and examined the visualization of the normal and abnormal ear (otitis media cholesteatoma) especially in terms of continuity in each of 20 patients. We would here like to report the favorable results together with some literature review. (author)

  14. Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

    International Nuclear Information System (INIS)

    Azarine, A.; Lions, C.; Beregi, J.P.; Koussa, M.

    2001-01-01

    A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation. (orig.)

  15. Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Azarine, A.; Lions, C.; Beregi, J.P. [Dept. of Vascular Surgery, Hopital Cardiologique, CHRU de Lille (France); Koussa, M. [Dept. of Vascular Radiology, Hopital Cardiologique, CHRU de Lille (France)

    2001-08-01

    A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation. (orig.)

  16. Helical CT of congenital ossicular anomalies

    International Nuclear Information System (INIS)

    Osada, Hisato; Machida, Kikuo; Honda, Norinari

    2001-01-01

    Since January 1996 to December 2000, 26 cases of congenital ossicular anomaly could be diagnosed with helical CT. All cases were unilateral. In 8 patients with malformation of the external ear, CT showed malleoincudal fixation (n=5), malleoincudal fixation and deformed incuts long process (n=1), deformed incus long process (n=1), and partial fusion of malleus neck and incus long process (n=1). In 18 patients with normal external ear, CT showed defect of the incus long process (n=5), defect of both the incus long process and stapes superstructure (n=8, 2 patients with congenital cholesteatoma, 1 with hypoplastic oval window), defect of the stapes superstructure (n=2, 1 patient with oval window absence), defect of the malleus manubrium (n=1), ossification of the stampede's tendon (n=1), and monopod stapes (n=1). Helical CT can evaluate the auditory ossicular chain in detail and is useful for diagnosing congenital ossicular anomaly. (author)

  17. Approximations of noise covariance in multi-slice helical CT scans: impact on lung nodule size estimation.

    Science.gov (United States)

    Zeng, Rongping; Petrick, Nicholas; Gavrielides, Marios A; Myers, Kyle J

    2011-10-07

    Multi-slice computed tomography (MSCT) scanners have become popular volumetric imaging tools. Deterministic and random properties of the resulting CT scans have been studied in the literature. Due to the large number of voxels in the three-dimensional (3D) volumetric dataset, full characterization of the noise covariance in MSCT scans is difficult to tackle. However, as usage of such datasets for quantitative disease diagnosis grows, so does the importance of understanding the noise properties because of their effect on the accuracy of the clinical outcome. The goal of this work is to study noise covariance in the helical MSCT volumetric dataset. We explore possible approximations to the noise covariance matrix with reduced degrees of freedom, including voxel-based variance, one-dimensional (1D) correlation, two-dimensional (2D) in-plane correlation and the noise power spectrum (NPS). We further examine the effect of various noise covariance models on the accuracy of a prewhitening matched filter nodule size estimation strategy. Our simulation results suggest that the 1D longitudinal, 2D in-plane and NPS prewhitening approaches can improve the performance of nodule size estimation algorithms. When taking into account computational costs in determining noise characterizations, the NPS model may be the most efficient approximation to the MSCT noise covariance matrix.

  18. 3D CT versus axial helical CT versus conventional tomography in the classification of acetabular fractures: A ROC analysis

    International Nuclear Information System (INIS)

    Kickuth, Ralph; Laufer, Ulf; Hartung, Guido; Gruening, Christian; Stueckle, Christoph; Kirchner, Johannes

    2002-01-01

    AIM: To assess the diagnostic power of three-dimensional computed tomography (3D CT), axial helical computed tomography (CT) and conventional tomography in the classification of acetabular fractures by interdisciplinary review. MATERIALS AND METHODS: Receiver operating characteristics (ROCs) were assessed for two radiologists and two surgeons blinded to the presence of acetabular fractures in an animal model (a total of 62 porcine hips, 40 of them with artificial acetabular fractures). Main target parameter was the diagnostic accuracy in the classification of the artificial fractures following Judet et al. RESULTS: ROC analysis for radiologists showed A z values of 0·83 for 3D CT, 0·81 for axial helical CT, and 0·78 for conventional tomography; differences between the three techniques were not significant (P = 0·46-0·73). A z values for the surgeons were 0·87 for 3D CT, 0·68 for axial helical CT, and 0·60 for conventional tomography; 3D CT was significantly better than axial helical CT (P = 0·01) and conventional tomography (P = 0·001). The differences between axial helical CT and conventional tomography were not significant (P = 0·37). CONCLUSION: Acetabular fractures are best classified by 3D CT, followed by axial helical CT and conventional tomography when assessed by surgeons. 3D CT did not provide any additional significant benefit in the classification performed by radiologists. Kickuth, R. et al. (2002)

  19. Optimization of multi-slice helical respiration-correlated CT: the effects of table speed and rotation time

    International Nuclear Information System (INIS)

    Wink, Nicole M; McNitt-Gray, Michael F; Solberg, Timothy D

    2005-01-01

    While respiration-correlated CT is gaining acceptance in clinical radiotherapy, the effect of scanning parameters on the image quality has yet to be addressed. The intent of this study was to characterize the effects of gantry rotation and table speed on various image quality characteristics in multi-slice, helical, retrospectively-gated CT images. Images of stationary and moving phantoms were obtained in helical mode on a 20-slice CT scanner. Motion was generated by a computer-controlled platform capable of moving simultaneously in two dimensions. Motion was monitored using a pressure gauge inserted inside an adjustable belt. Selected scans were retrospectively gated into ten phases based on the monitored motion. Gantry rotation speeds of 0.5 s and 1.0 s were evaluated with pitches ranging from 0.1 to 0.45. Several parameters, including calculated object volumes, trajectory (movement from peak to trough), deformation (actual volume divided by volume created with the maximum diameter of contoured object) and z-axis resolution, were used to characterize image quality. These studies indicate that for objects in the peak phase of a movement pattern that simulates breathing, retrospectively gated scans using fast gantry rotation speeds produce volume, trajectory, deformation and z-axis resolution results comparable with those of a stationary object

  20. Role of contrast-enhanced helical CT in the evaluation of acute thoracic aortic injuries after blunt chest trauma

    International Nuclear Information System (INIS)

    Scaglione, M.; Pinto, A.; Pinto, F.; Romano, L.; Ragozzino, A.; Grassi, R.

    2001-01-01

    The purpose of this retrospective study was to determine the value of contrast-enhanced helical CT for detecting and managing acute thoracic aortic injury (ATAI). Between June 1995 and February 2000, 1419 consecutive chest CT examinations were performed in the setting of major blunt trauma. The following CT findings were considered indicative of ATAI: intimal flap; pseudoaneurysm; contour irregularity; lumen abnormality; and extravasation of contrast material. On the basis of these direct findings no further diagnostic investigations were performed. Isolated mediastinal hematoma on CT scans was considered an indirect sign of ATAI: In these cases, thoracic aortography was performed even if CT indicated normal aorta. Seventy-seven patients had abnormal CT scans: Among the 23 patients with direct CT signs, acute thoracic aortic injuries was confirmed at thoracotomy in 21. Two false-positive cases were observed. The 54 remaining patients had isolated mediastinal hematoma without aortic injuries at CT and corresponding negative angiograms. The 1342 patients with negative CT scans were included in the 8-month follow-up program and did not show any adverse sequela based on clinical and radiographic criteria. Contrast-enhanced helical CT has a critical role in the exclusion of thoracic aortic injuries in patient with major blunt chest trauma and prevents unnecessary thoracic aortography. Direct CT signs of ATAI do not require further diagnostic investigations to confirm the diagnosis: Isolated aortic bands or contour vessel abnormalities should be first considered as possible artifacts or related to non-traumatic etiologies especially when mediastinal hematoma is absent. In cases of isolated mediastinal hematoma other possible sources of bleeding should be considered before directing patients to thoracic aortography. (orig.)

  1. Diagnosis of deep vein thrombosis using multi-detector helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masashi; Minamiguchi, Hiroki; Sahara, Shinya [Wakayama Medical Coll. (Japan)] [and others

    2002-11-01

    The purpose of this study was to evaluate the usefulness of multi-detector helical CT (MDHCT) with contrast medium in the diagnosis of deep vein thrombosis (DVT). The bilateral veins of the dorsal pedis in 45 patients (12 men, 33 women; average age, 64 years) under clinical suspicion of DVT were first punctured using 22-G needles. Then CT scanning from the level of the foot to the inferior vena cava was started 20 sec after the initial injection of 200 mL of dilute contrast medium (50 mL nonionic iodinated contrast medium of 300 mgI/mL and 150 mL saline) at a rate of 5 mL/sec. Two patients were excluded because of unsuccessful venous puncture. The average scanning time in 43 patients was 38.5{+-}7.9 seconds. Images of veins from the foot to the inferior vena cava were clearly demonstrated in each case. MDHCT showed DVT in 32 cases and patent deep vein in 11 cases. Simultaneous venography of the lower extremity in 18 patients clearly visualized DVT at the same level detected by contrast MDHCT. MDHCT for the diagnosis of DVT has the advantages of wider scanning rage, shorter scanning time, and finer Z-axis resolution than the other diagnostic modalities. (author)

  2. Diagnosis of deep vein thrombosis using multi-detector helical CT

    International Nuclear Information System (INIS)

    Kimura, Masashi; Minamiguchi, Hiroki; Sahara, Shinya

    2002-01-01

    The purpose of this study was to evaluate the usefulness of multi-detector helical CT (MDHCT) with contrast medium in the diagnosis of deep vein thrombosis (DVT). The bilateral veins of the dorsal pedis in 45 patients (12 men, 33 women; average age, 64 years) under clinical suspicion of DVT were first punctured using 22-G needles. Then CT scanning from the level of the foot to the inferior vena cava was started 20 sec after the initial injection of 200 mL of dilute contrast medium (50 mL nonionic iodinated contrast medium of 300 mgI/mL and 150 mL saline) at a rate of 5 mL/sec. Two patients were excluded because of unsuccessful venous puncture. The average scanning time in 43 patients was 38.5±7.9 seconds. Images of veins from the foot to the inferior vena cava were clearly demonstrated in each case. MDHCT showed DVT in 32 cases and patent deep vein in 11 cases. Simultaneous venography of the lower extremity in 18 patients clearly visualized DVT at the same level detected by contrast MDHCT. MDHCT for the diagnosis of DVT has the advantages of wider scanning rage, shorter scanning time, and finer Z-axis resolution than the other diagnostic modalities. (author)

  3. Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Pan, Yuxi; Qiu, Rui; Ge, Chaoyong; Xie, Wenzhang; Li, Junli; Gao, Linfeng; Zheng, Junzheng

    2014-01-01

    With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations. (paper)

  4. Three-dimensional helical (spiral) CT angiography. Visualization of vessels in the maxillofacial regions

    International Nuclear Information System (INIS)

    Hanawa, Shigeo; Sakamoto, Hidetomo; Mori, Shin-ichiro; Kagawa, Toyohiro; Seze, Ryosuke; Ishioka, Hisakazu; Tashiro, Himiko; Ogawa, Kazuhisa; Wada, Tadako

    1998-01-01

    Authors performed the contrast helical CT for tumors on the maxillofacial regions, and reconstituted these data into the three-dimensional helical (spiral) CT angiography (CTA). Furthermore the conditions of photographing and the clinical significance of CTA were discussed. The subjects were 24 cases (including 13 of malignant tumors, 4 of benign tumors, 4 of inflammation and 3 of malformations), to which the contrast helical CT was performed transvenously. The photographing condition was set in principal to 140 kV of the tube voltage, 160 (200) mA of the tube current, 3 mm of the X-ray beam width, 3 mm/sec (pitch=1) of the turn-table moving speed. The relationship between the beam width and the pitch was determined by the phantom experiments. The scanning was carried out maximally for continuous 60 sec as the scanning time of a turn/sec. Of all cases, CTA visualized three-dimensionally vessels, but it was hard in the total carotid arteries and the internal-external carotid arteries. Authors analyzed the axial and the multiplanar reconstitution (MPR) images as the two-dimensional display, and the surface rendering (SR), the volume rendering and the maximum intensity projections (MIP) as the three-dimensional display. The axial and MPR image of the facial arteries and the lingual arteries as the branched vessels from the external carotid arteries were recognized easily. By SR, it was easily to understand the anatomical relationship among vessels, gnathic bone and cervical vertebrae, and by MIP sufficiently observe the concentration dependent calcification of the vessel walls. Three-dimensional CTA is very useful to get the three-dimensional visual information about the anatomical structures of the maxillofacial regions which is necessary for oral surgeons to plan the pre-operational strategies. (K.H.)

  5. [Comparison of radiation dose reduction of prospective ECG-gated one beat scan using 320 area detector CT coronary angiography and prospective ECG-gated helical scan with high helical pitch (FlashScan) using 64 multidetector-row CT coronary angiography].

    Science.gov (United States)

    Matsutani, Hideyuki; Sano, Tomonari; Kondo, Takeshi; Fujimoto, Shinichiro; Sekine, Takako; Arai, Takehiro; Morita, Hitomi; Takase, Shinichi

    2010-12-20

    A high radiation dose associated with 64 multidetector-row computed tomography (64-MDCT) is a major concern for physicians and patients alike. A new 320 row area detector computed tomography (ADCT) can obtain a view of the entire heart with one rotation (0.35 s) without requiring the helical method. As such, ADCT is expected to reduce the radiation dose. We studied image quality and radiation dose of ADCT compared to that of 64-MDCT in patients with a low heart rate (HR≤60). Three hundred eighty-five consecutive patients underwent 64-MDCT and 379 patients, ADCT. Patients with an arrhythmia were excluded. Prospective ECG-gated helical scan with high HP (FlashScan) in 64 was used for MDCT and prospective ECG-gated conventional one beat scan, for 320-ADCT. Image quality was visually evaluated by an image quality score. Radiation dose was estimated by DLP (mGy・cm) for 64-MDCT and DLP.e (mGy・cm) for 320-ADCT. Radiation dose of 320-ADCT (208±48 mGy・cm) was significantly (P<0.0001) lower than that of 64-MDCT (484±112 mGy・cm), and image quality score of 320-ADCT (3.0±0.2) was significantly (P=0.0011) higher than that of 64-MDCT (2.9±0.4). Scan time of 320-ADCT (1.4±0.1 s) was also significantly (P<0.0001) shorter than that of 64-MDCT (6.8±0.6 s). 320-ADCT can achieve not only a reduction in radiation dose but also a superior image quality and shortening of scan time compared to 64-MDCT.

  6. Helical CT defecography; La defecografia con Tomografia Computerizzata spirale

    Energy Technology Data Exchange (ETDEWEB)

    Ferrando, R.; Fiorini, G.; Beghello, A.; Cicio, G.R.; Derchi, L.E.; Consigliere, M.; Resasco, M. [Genua Univ., Genua (Italy). Ist. di Radiologia, Cattedra R; Tornago, S. [Genua Univ. Genua (Italy). 2 Clinica Ortopedica

    1999-11-01

    The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus examined supine. Twenty-second helical scans were performed at rest and during evacuation; multiplanar reconstructions were obtained especially on the sagittal plane for comparison with conventional defecographic images. Coronal Helical CT defecography images permitted to map the perineal floor muscles, while sagittal reconstructions provided information on the ampulla and the levator ani. To conclude, Helical CT defecography performed well in study of pelvic floor disorders and can follow conventional defecography especially in questionable cases. [Italian] Scopo di questo lavoro e' ricercare un ruolo per la defeco-TC con apparecchiatura elicoidale nello studio delle malattie del pavimento pelvico confrontandola con i risultati consolidati della defecografia tradizionale. Si sono visionati 90 pazienti, 62 femmine e 28 maschi, con eta' compresa tra 24 e 82 anni, con defecografia tradizionale; di questi, 18 casi con diagnosi dubbia sono stati studiati anche con defeco-TC spirale

  7. Diagnostic value of triphasic incremental helical CT in early and progressive gastric carcinoma

    International Nuclear Information System (INIS)

    Gao Jianbo; Yan Xuehua; Li Mengtai; Guo Hua; Chen Xuejun; Guan Sheng; Zhang Xiefu; Li Shuxin; Yang Xiaopeng

    2001-01-01

    Objective: To investigate helical CT enhancement characteristics of gastric carcinoma, and the diagnostic value and preoperative staging of gastric carcinoma with triphasic incremental helical CT of the stomach with water-filling method. Methods: Both double-contrast barium examination and triphasic incremental helical CT of the stomach with water-filling method were performed in 46 patients with gastric carcinoma. Results: (1) Among these patients, normal gastric wall exhibited one layered structure in 18 patients, two or three layered structure in 28 patients in the arterial and portal venous phase. (2) Two cases of early stomach cancer showed marked enhancement in the arterial and portal venous phase and obvious attenuation of enhancement in the equilibrium phase. On the contrary, 32 of the 44 advanced gastric carcinoma was showed marked enhancement in the venous phase compared with the arterial phase ( t = 4.226, P < 0.05). (3) The total accuracy of triphasic incremental helical CT in determining TNM-staging was 81.0%. Conclusion: Different types of gastric carcinoma have different enhancement features. Triphases incremental helical CT is more accurate than conventional CT in the preoperative staging of gastric carcinoma

  8. Helical CT for emergency patients with cerebrovascular diseases. Diagnosis of cerebral aneurysms with subarachnoid hemorrhage (SAH) by three-dimensional CT angiography (3D-CTA)

    International Nuclear Information System (INIS)

    Matsumoto, Masato; Satoh, Naoki; Kobayashi, Touru; Kodama, Namio; Nakano, Masayuki; Watanabe, Youichi; Fujii, Masayuki

    1996-01-01

    Recently, the usefulness of three-dimensional CT angiography (3D-CTA) using helical CT has been reported. Although 3D-CTA has been applied for neurosurgical diseases, especially for surgical planning, it has not done for emergency patients because of the long time required for image reconstruction and location of a helical CT scanner. We studied emergency patients with SAH, and compared the 3D-CTA with angiography and surgical findings, using TOSHIBA X vigor. Twenty-two patients with SAH were evaluated. The helical CT was performed for 55 seconds with a bolus injection of 90 ml non-ionic, iodinated contrast medium at a rate of 3 ml/sec with a delay of 20 sec. Angiography was carried out immediately after the helical CT. Eighteen of 22 cases were operated on urgently. We were able to create the 3D-CTA in about 7 minutes, and diagnose aneurysms by the 3D-CTA before angiography. The 3D-CTA was able to demonstrate 30 of 31 aneurysms including 9 unruptured aneurysms. An unruptured internal carotid-posterior communicating artery aneurysm 1.3 mm in diameter and associated with a ruptured aneurysm was not detected by either the 3D-CTA or angiography. On the other hand, an unruptured Acom aneurysm 0.8 mm in diameter and associated with a ruptured aneurysm could be detected by the: 3D-CTA, but not by angiography. The 3D-CTA gave us useful information concerning the anatomical relationship of the aneurysm, its neck and parent artery, and the surrounding branches. There were no complications or side effects associated with the helical CT scan. Although the 3D-CTA requires further development of visualization of small arteries less than 1 mm in diameter, such as perforating arteries, subtraction technique of bony structure, and a method for checking cervical arteries, it is useful for diagnosis of emergency patients with SAH and urgent operations. We believe that an operation might be performed by only the 3D-CTA without the angiography in the near future. (author)

  9. Helical CT for emergency patients with cerebrovascular diseases. Diagnosis of cerebral aneurysms with subarachnoid hemorrhage (SAH) by three-dimensional CT angiography (3D-CTA)

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Masato; Satoh, Naoki; Kobayashi, Touru; Kodama, Namio; Nakano, Masayuki; Watanabe, Youichi; Fujii, Masayuki [Fukushima Medical School (Japan)

    1996-05-01

    Recently, the usefulness of three-dimensional CT angiography (3D-CTA) using helical CT has been reported. Although 3D-CTA has been applied for neurosurgical diseases, especially for surgical planning, it has not done for emergency patients because of the long time required for image reconstruction and location of a helical CT scanner. We studied emergency patients with SAH, and compared the 3D-CTA with angiography and surgical findings, using TOSHIBA X vigor. Twenty-two patients with SAH were evaluated. The helical CT was performed for 55 seconds with a bolus injection of 90 ml non-ionic, iodinated contrast medium at a rate of 3 ml/sec with a delay of 20 sec. Angiography was carried out immediately after the helical CT. Eighteen of 22 cases were operated on urgently. We were able to create the 3D-CTA in about 7 minutes, and diagnose aneurysms by the 3D-CTA before angiography. The 3D-CTA was able to demonstrate 30 of 31 aneurysms including 9 unruptured aneurysms. An unruptured internal carotid-posterior communicating artery aneurysm 1.3 mm in diameter and associated with a ruptured aneurysm was not detected by either the 3D-CTA or angiography. On the other hand, an unruptured Acom aneurysm 0.8 mm in diameter and associated with a ruptured aneurysm could be detected by the: 3D-CTA, but not by angiography. The 3D-CTA gave us useful information concerning the anatomical relationship of the aneurysm, its neck and parent artery, and the surrounding branches. There were no complications or side effects associated with the helical CT scan. Although the 3D-CTA requires further development of visualization of small arteries less than 1 mm in diameter, such as perforating arteries, subtraction technique of bony structure, and a method for checking cervical arteries, it is useful for diagnosis of emergency patients with SAH and urgent operations. We believe that an operation might be performed by only the 3D-CTA without the angiography in the near future. (author)

  10. The role of 3D Helical CT in the reconstructive treatment of maxillofacial cancers

    International Nuclear Information System (INIS)

    De Rosa, V.; Ziviello, M.; Ionna, F.; Mozzillo, N.; Parascandolo, S.

    2000-01-01

    Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micro nets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated bovine pericardium was affixed and moduled on the borders in two cases only. Three-dimensionally reconstructed CT images were obtained preoperatively and at least 6 months postoperatively in all patients. The images were generated on a computer workstation using the shaded surface display (SSD) software with threshold values ranging 425 to 630 HU, and a more closed window for the imaging of titanium mesh/bone interface in the post surgical follow-up. It was obtained an excellent complete spatial depiction of maxillo facial region both before and after surgery, with no artefacts so important as to affect the 3D reconstruction process and the image quality. Together with the head-neck surgical team it could be worked for preoperative planning through CT scans by different 3D points of view. The 3D reconstructed follow-up scans showed good filling of the defect in the area where the titanium mesh had been used. Then efficacious bone modelling and good biocompatibility of the alloplastic material were seen in all patients, with no inflammatory reactions. Titanium is a well-known material, which is widely used for cranioplasty. It is a radiolucent, non

  11. Multislice helical CT in the diagnosis of hilar cholangiocarcinoma

    International Nuclear Information System (INIS)

    Yang Li; Zhao Shaohong; Nie Yongkang; Zhao Hong; Fang Jie; Cai Zulong; Yang Zhou; Ying Yifeng

    2005-01-01

    Objective: To investigate the value ofMSCT in observing the direct findings of hilar cholangiocarcinoma1Methods Multislice helical CT studies were performed on the upper abdomen in 19 consecutive patientswith painless jaundice1 Precontrast and dynamic contrast enhanced (25 s phase and 60 s phase) scanswere conducted, and 3D imageswere reconstructed using enhanced raw data in 15 cases1 The direct CT findings of hilar cholangiocarcinoma were studied by three radiologists respectively in a 32scale strategy1 The morphological features and extension of bile duct involvement by hilar cholangiocarcinoma were analyzed1 All the 19 caseswere pathologically p roved as hilar cholangiocarcinoma by surgery (15 cases) and ERCP ( 4 cases) 1 Results The direct findings and extension of hilar cholangiocarcinoma could be demonstrated in 14 out of 15 3D reconstruction images, 8 out of 19 in 25 s phase, and 7 out of 19 in 60 s phase of contrast enhancement scans, respectively ( P < 0105 ) 1 The tumor involving the bile duct was enhanced most remarkablely on 25 s phase, and the bile duct wall thickening, bile duct narrowing or occlusion were demonstrated as the p rimary findings of hilar cholangiocarcinoma1 The intraductal sp read of tumor could be demonstrated as small nodules on the bile duct wall p roximal or distal to the tumor1 Conclusion. The tumor involving the bile duct can be enhanced most remarkablely on 25 s phase after contrast injection1 Multislice helical CT, especially 3D reconstructed images, can be used to detect the direct findings of hilar cholangiocarcinomas and the extension of tumor involving the bile duct. (authors)

  12. Respiratory gated lung CT using 320-row area detector CT

    International Nuclear Information System (INIS)

    Sakamoto, Ryo; Noma, Satoshi; Higashino, Takanori

    2010-01-01

    Three hundred and twenty-row Area Detector CT (ADCT) has made it possible to scan whole lung field with prospective respiratory gated wide volume scan. We evaluated whether the respiratory gated wide volume scan enables to reduce motion induced artifacts in the lung area. Helical scan and respiratory gated wide volume scan were performed in 5 patients and 10 healthy volunteers under spontaneous breathing. Significant reduction of motion artifact and superior image quality were obtained in respiratory gated scan in comparison with helical scan. Respiratory gated wide volume scan is an unique method using ADCT, and is able to reduce motion artifacts in lung CT scans of patients unable to suspend respiration in clinical scenes. (author)

  13. Single-slice rebinning method for helical cone-beam CT

    International Nuclear Information System (INIS)

    Noo, F.; Defrise, M.; Clackdoyle, R.

    1999-01-01

    In this paper, we present reconstruction results from helical cone-beam CT data, obtained using a simple and fast algorithm, which we call the CB-SSRB algorithm. This algorithm combines the single-slice rebinning method of PET imaging with the weighting schemes of spiral CT algorithms. The reconstruction is approximate but can be performed using 2D multislice fan-beam filtered backprojection. The quality of the results is surprisingly good, and far exceeds what one might expect, even when the pitch of the helix is large. In particular, with this algorithm comparable quality is obtained using helical cone-beam data with a normalized pitch of 10 to that obtained using standard spiral CT reconstruction with a normalized pitch of 2. (author)

  14. Aortic non communicating dissections. A study with helical CT

    International Nuclear Information System (INIS)

    Midiri, M.; Strada, A.; Stabile Ianora, A.A.; Rotondo, A.; Angelelli, G.; D'Agostino, D.; De Luca Tupputi Schinosa, L.

    2000-01-01

    The evaluate the signs of aortic intramural hematoma with helical CT and the diagnostic role of this technique in patients with this condition. It was reviewed the CT findings of 396 patients submitted to emergency examinations for suspected aortic dissection from 1995 to 1999. Only 18 patients (6 women and 12 men) had CT signs of aortic intramural hematoma. Helical CT studies were carried out with the following parameters: slice thickness 10 mm, reconstruction index 10, feed 1.5 mm, conventional algorithm with minimum values of 130 kV and 125mA. All patients were examined with dynamic contrast-enhanced CT, before and after a power injection of 130 mL ionic contrast material. It was studied: hematoma localization and longitudinal extension; thickness and density of aortic wall; presence and location of intimal calcifications; integrity of intimal wall; hemo mediastinum and/or hemo thorax. Aortic wall thickening appeared as a high density crescent-shaped area at baseline CT and had low density on enhanced images in all patients. Thickening was eccentric in 14/18 patients and concentric in 4/18 only; it always exceeded 4 mm. It was found some intimal calcifications in 8 patients and hemo thorax and/or hemo mediastinum in 9 patients. A patient with type A hematoma died of cardiac tamponade a few hours after CT diagnosis. Six patients (5 type B and 1 type A) underwent anti-hypertensive treatment and radiological follow-up. Eleven patients (6 type A and 5 type B) underwent prosthesis replacement and 5 of them (3 type A and 2 type B) died of postoperative complications. In the 5 type B patients surgery was performed because of treatment-resistant pain and of the onset of ischemic complications to abdominal organs caused by involvement of the main collateral branches of the aorta. One patient with type A hematoma was submitted to drug treatment because it was judged unresectable. Intramural hematoma of the aorta is a distinct pathological entity, which should not be

  15. Dose reduction using prospective electrocardiograph-triggered axial coronary scan on the 64-slice spiral CT

    International Nuclear Information System (INIS)

    Wang Yanyan; Wu Guogeng; Zhou Cheng; Gao Jianhua; Jiao Sheng; Cao Huizhi

    2008-01-01

    Objective: To compare radiation dose and image quality between prospective electrocardiograph (ECG)-triggered axial scan and retrospective ECG-gated helical scan in coronary 64-slice CT angiography (CTA). Methods: Seventy-seven consecutive patients [group A. Average body mass index (BMI): 24.6, heart rate 0.05). Conclusion: Prospective ECG-triggered axial scan in 64-slice coronary CTA can significantly reduce radiation exposure and the image quality can fulfill clinical diagnostic needs. (authors)

  16. Effect of CT contrast on volumetric arc therapy planning (RapidArc and helical tomotherapy) for head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Alan J.; Vora, Nayana [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States); Suh, Steve [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Liu, An, E-mail: aliu@coh.org [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Schultheiss, Timothy E. [Department of Radiation Physics, City of Hope National Medical Center, Duarte, CA (United States); Wong, Jeffrey Y.C. [Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA (United States)

    2015-04-01

    The objectives of the study were to evaluate the effect of intravenous contrast in the dosimetry of helical tomotherapy and RapidArc treatment for head and neck cancer and determine if it is acceptable during the computed tomography (CT) simulation to acquire only CT with contrast for treatment planning of head and neck cancer. Overall, 5 patients with head and neck cancer (4 men and 1 woman) treated on helical tomotherapy were analyzed retrospectively. For each patient, 2 consecutive CT scans were performed. The first CT set was scanned before the contrast injection and secondary study set was scanned 45 seconds after contrast. The 2 CTs were autoregistered using the same Digital Imaging and Communications in Medicine coordinates. Tomotherapy and RapidArc plans were generated on 1 CT data set and subsequently copied to the second CT set. Dose calculation was performed, and dose difference was analyzed to evaluate the influence of intravenous contrast media. The dose matrix used for comparison included mean, minimum and maximum doses of planning target volume (PTV), PTV dose coverage, and V{sub 45} {sub Gy}, V{sub 30} {sub Gy}, and V{sub 20} {sub Gy} organ doses. Treatment planning on contrasted images generally showed a lower dose to both organs and target than plans on noncontrasted images. The doses for the points of interest placed in the organs and target rarely changed more than 2% in any patient. In conclusion, treatment planning using a contrasted image had insignificant effect on the dose to the organs and targets. In our opinion, only CT with contrast needs to be acquired during the CT simulation for head and neck cancer. Dose calculations performed on contrasted images can potentially underestimate the delivery dose slightly. However, the errors of planning on a contrasted image should not affect the result in clinically significant way.

  17. Comparison of AMI-25 enhanced MRI and helical dynamic CT in the detection of hepatic lesions

    International Nuclear Information System (INIS)

    Saitou, Kazuhiro; Matsuda, Hiromichi; Fukushima, Hiroaki; Kanzaki, Hiroshi; Hirose, Takashi; Karizaki, Dai; Abe, Kimihiko; Amino, Saburou

    1994-01-01

    We performed AMI-25 enhanced MRI and helical dynamic CT in 12 cases of hepatic lesions. Nine of these were hepatocellular carcinomas. Two cases were metastatic liver tumors (the primary lesion was gastric in one and the other was gallbladder cancer). One case was suspected to be adenomatous hyperplasia. Thirty-two lesions were detected in T2-weighted SE images before AMI-25 administration, while 46 lesions were detected in AMI-25 enhanced MRI images. In particular, AMI-25 enhanced MRI was superior to plain MRI in lesions less than 10 mm in size. A total of 48 lesions were detected in helical dynamic CT. Although AMI-25 enhanced MRI almost equaled helical dynamic CT in the detection of liver tumors, helical dynamic CT was slightly superior to AMI-25 enhanced MRI in the detection of subphrenic lesions. It was possible to know the hemodynamics in each hepatic lesion by helical dynamic CT. AMI-25 enhanced MRI was useful to know the inclusion of reticuloendothelial system, and that yielded different diagnoses in adenomatous hyperplasia and well differentiated hepatocellular carcinoma. Helical dynamic CT was useful for qualitative diagnosis. Both AMI-25 enhanced MRI and helical dynamic CT contributed to the detection of liver tumor and qualitative diagnosis. (author)

  18. Computed Tomography (CT) Scans and Cancer

    Science.gov (United States)

    ... Reporting & Auditing Grant Transfer Grant Closeout Contracts & Small Business Training Cancer Training at NCI (Intramural) Resources for ... companies (and Medicare) do not currently reimburse the costs of this procedure. Also, because CT ... the effectiveness of low-dose helical CT for lung cancer ...

  19. Partial volume and aliasing artefacts in helical cone-beam CT

    International Nuclear Information System (INIS)

    Zou Yu; Sidky, Emil Y; Pan, Xiaochuan

    2004-01-01

    A generalization of the quasi-exact algorithms of Kudo et al (2000 IEEE Trans. Med. Imaging 19 902-21) is developed that allows for data acquisition in a 'practical' frame for clinical diagnostic helical, cone-beam computed tomography (CT). The algorithm is investigated using data that model nonlinear partial volume averaging. This investigation leads to an understanding of aliasing artefacts in helical, cone-beam CT image reconstruction. An ad hoc scheme is proposed to mitigate artefacts due to the nonlinear partial volume and aliasing artefacts

  20. The evaluation study of helical CT for hepatocellular carcinoma with microwave coagulation treatment

    International Nuclear Information System (INIS)

    Zheng Keguo; Xu Dasheng; Xie Xiaoyan; Peng Zhenpeng

    2002-01-01

    Objective: To study the helical CT signs of the hepatocellular carcinoma (HCC) after percutaneous microwave coagulation therapy (PMCT) and to evaluate the correlation between the helical CT signs and the therapeutic effect of HCC. Methods: The helical CT signs were analyzed in 22 cases with 26 lesions of the hepatocellular carcinoma that were treated with PMCT under ultrasonic guidance. Results: In 21 lesions, no enhancement was detected in the lesion border or inside the lesion at hepatic arterial phase (HAP) and portal venous phase (PVP). In 7 lesions, the slight or marked patchy enhancement was revealed in the surrounding liver of the lesions in HAP. In 5 lesions, nodular enhancement was found in the lesion border or inside the lesion in HAP. Conclusion: The dual-phase helical CT might be accurate in judging the therapeutic effect of HCC after PMCT. If no enhancement was showed in the lesions in the dual-phase helical CT, it indicated that no tumor survived. If slight or marked patchy pattern enhancement was revealed in the surrounding liver of the lesions in HAP, it was a normal reaction after PMCT. If nodular enhancement was found in the lesion border or inside the lesion in HAP, it indicated that the tumor partially survived

  1. Early clinical phase of patient's management after polytrauma using 1- and 4-slice helical CT

    International Nuclear Information System (INIS)

    Kloeppel, R.; Kahn, T.; Schreiter, D.; Dietrich, J.; Josten, C.

    2002-01-01

    In the early clinical phase the comprehensive imaging of patients with multiple trauma using helical CT is already established. Aim of this study was to assess whether MSCT may improve the patient management and the diagnostic results.The procedure is designed as follows: after life-thretening treatment x-ray of chest and ultrasound are carried out in the emergency room. Then the patient is moved to CT. From 1998 to december 2000 241 patients were examined using a single slice helical CT (Somatom plus 4), in 2001 79 patients using a 4-slice helical CT (Somatom VZ, Siemens Med.Sol.). After CT selected radiograms of the extremities were taken.359 of 360 procedures were carried out successfully. Excluding 1 case (death during 1-sl. h CT) all relevant lesions of head, neck, and body were diagnosed. Although the patients had an injury severity score of ∼30. The change from 1slice-helical CT to 4 slice-helical CT allowed us to reduce the stay in the CT room from 28 to 16 min. The total lethality decreased by ∼4%.Advantages for the patient arose from the standardized examination protocol using multislice CT. If integrated in an interdisciplinary management concept, it is a good compromise between examination time, comprehensive diagnostic imaging, life-saving therapeutic procedures, and therapy planning. (orig.) [de

  2. Scanning and contrast enhancement protocols for multi-slice CT in evaluation of the upper abdomen

    International Nuclear Information System (INIS)

    Awai, Kazuo; Onishi, Hiromitsu; Takada, Koichi; Yamaguchi, Yasuo; Eguchi, Nobuko; Hiraishi, Kumiko; Hori, Shinichi

    2000-01-01

    The advent of multi-slice CT is one of the quantum leaps in computed tomography since the introduction of helical CT. Multi-slice CT can rapidly scan a large longitudinal (z-axis) volume with high longitudinal resolution and low image artifacts. The rapid volume coverage speed of multi-slice CT can increase the difficulty in optimizing the delay time between the beginning of contrast material injection and the acquisition of images and we need accurate knowledge about optimal temporal window for adequate contrast enhancement. High z-axis resolution of multi-slice can improve the quality of three-dimensional images and MPR images and we must select adequate slice thickness and slice intervals in each case. We discuss basic considerations for adequate contrast enhancement and scanning protocols by multi-slice CT scanner in the upper abdomen. (author)

  3. CT scanning in pediatric head trauma: correlation of clinical features with CT scan diagnosis

    International Nuclear Information System (INIS)

    Arkoncel, Mary Ann P.; Posadas, Ma. Belen A.

    1997-01-01

    A retrospective review was conducted on 205 cases of pediatric head trauma for which cranial computed tomography scans were done at the Makati Medical Center, to determine which clinical features might positively predict an abnormality on CT scan. The clinical findings of loss of consciousness, GCS < 12, vomiting headache, seizures, and focal abnormalities on Neurologic Examination were significantly associated with abnormal findings on CT scan. However, a significant discrepancy does exist as to how accurately clinical findings do in fact predict normal and abnormal CT scan findings. Such a discrepancy allows us to conclude that a more liberal use of CT Scanning in cases of pediatric head trauma must be stressed to insure proper diagnosis. This study shows that when a patient presents with the aforementioned positive signs and symptoms, or with a focal neurologic deficit, or in combination, a 60-100 % positive prediction of abnormal CT Scan can be made. However, prediction of normal CT Scan is only 0-40%. (Author)

  4. Aquilion ONE / ViSION Edition CT scanner realizing 3D dynamic observation with low-dose scanning

    International Nuclear Information System (INIS)

    Kazama, Masahiro; Saito, Yasuo

    2015-01-01

    Computed tomography (CT) scanners have been continuously advancing as essential diagnostic imaging equipment for the diagnosis and treatment of a variety of diseases, including the three major disease classes of cerebrovascular disease, cardiovascular disease, and cancer. Through the development of helical CT scanners and multislice CT scanners, Toshiba Medical Systems Corporation has developed the Aquilion ONE, a CT scanner with a scanning range of up to 160 mm per rotation that can obtain three-dimensional (3D) images of the brain, heart, and other organs in a single rotation. We have now developed the Aquilion ONE / ViSION Edition, a next-generation 320-row multislice CT scanner incorporating the latest technologies that achieves a shorter scanning time and significant reduction in dose compared with conventional products. This product with its low-dose scanning technology will contribute to the practical realization of new diagnosis and treatment modalities employing four-dimensional (4D) data based on 3D dynamic observations through continuous rotations. (author)

  5. Exabyte helical scan devices at Fermilab

    International Nuclear Information System (INIS)

    Constanta-Fanourakis, P.; Kaczar, K.; Oleynik, G.; Petravick, D.; Votava, M.; White, V.; Hockney, G.; Bracker, S.; de Miranda, J.M.

    1989-05-01

    Exabyte 8mm helical scan storage devices are in use at Fermilab in a number of applications. These devices have the functionality of magnetic tape, but use media which is much more economical and much more dense than conventional 9 track tape. 6 refs., 3 figs

  6. Usefulness of unenhanced helical CT in patients with suspected ureteral colic

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Soo; Nam Kung, Sook; Kim, Heung Cheol; Hwang, Woo Chul; Lee, In Sun; Hwang, Im Kyung; Kim, Ho Chul; Bae, Sang Hoon; Lee, Sang Kon; Lee, Seong Ho [College of Medicine, Hallym Univ., Chunchon (Korea, Republic of)

    2002-07-01

    To determine the usefulness of unenhanced helical CT in patients with suspected renal colic. One hundred and fourteen patients with suspected ureteral colic, referred by physicians, underwent unenhanced helical CT. Two radiologists prospectively interpreted the results, determining the presence or absence of ureter stone and other diseases the arise outside the urinary tract. In cases of ureteral stone, we retrospectively sought secondary signs of hydronephrosis, perinephric fat stranding, thickening of renal fascia, renal enlargement, and the tissue rim sign. Among the 114 patients, 57 were confirmed as having ureter stones. Unenhanced helical CT depicted 57 of 58 stones in 57 patients, producing one false-negative and one false-positive result. Overall, the results showed 98% sensitivity, 95% specificity, 98% positive predictive value, 95% negative predictive value, and 97% accuracy. The frequencies of secondary signs were as follows: hydronephrosis, 95%(54/57); perinephric fat stranding, 81% (46/57); thickening of renal fascia, 77% (44/57); renal enlargement , 65%(37/57); and the tissure rim sign 72%(21/29). In 20 patients, the diagnoses were not related to stone disease and included one false-negative diagnosis of pyonephrosis. Unenhanced helical CT provides information which is valuable in the accurate diagnosis of ureteral stone as well as other diseases that arise outside the urinary tract in patients with suspected renal colic.

  7. Ligation of the internal maxillary artery for intractable epistaxis. 3D imaging of internal maxillary artery using helical CT scan

    International Nuclear Information System (INIS)

    Handa, Toru; Yazin, Koji; Hirakawa, Katsuhiro; Fukushima, Noriyuki; Takumida, Masaya; Hirata, Shitau; Iguchi, Tetsuhiko; Amano, Yoshiharu

    2001-01-01

    Sever posterior epistaxis is one of the serious clinical problems. Nasal bleeding usually occurs in the anterior septal region, where it can be seen easily and controlled with topical cautery or localized packing. When the bleeding occurs in the posterior nose, it becomes a more serious problem. Many methods have been used to control posterior epistaxis. Some of these are electrocautery, posterior nasal packing, vascular ligation and therapeutic percutaneous embolization. Between 1997 and 2000, nineteen patients were admitted to our hospital because of intractable epistaxis. There were 16 male and 3 female patients whose average age was 55 years. Ten of 19 patients were hypertensive, and none of these had undergoing treatment. Five of 19 patients received maxillary artery ligation. Clinical applications of 3D imaging of the internal maxillary artery using helical CT scan were done for 5 patients. These images were helpful for planning of ligation of the internal maxillary artery. (author)

  8. Ligation of the internal maxillary artery for intractable epistaxis. 3D imaging of internal maxillary artery using helical CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Handa, Toru [Akitsu Prefectual Hospital, Hiroshima (Japan); Yazin, Koji; Hirakawa, Katsuhiro; Fukushima, Noriyuki; Takumida, Masaya; Hirata, Shitau; Iguchi, Tetsuhiko; Amano, Yoshiharu

    2001-03-01

    Sever posterior epistaxis is one of the serious clinical problems. Nasal bleeding usually occurs in the anterior septal region, where it can be seen easily and controlled with topical cautery or localized packing. When the bleeding occurs in the posterior nose, it becomes a more serious problem. Many methods have been used to control posterior epistaxis. Some of these are electrocautery, posterior nasal packing, vascular ligation and therapeutic percutaneous embolization. Between 1997 and 2000, nineteen patients were admitted to our hospital because of intractable epistaxis. There were 16 male and 3 female patients whose average age was 55 years. Ten of 19 patients were hypertensive, and none of these had undergoing treatment. Five of 19 patients received maxillary artery ligation. Clinical applications of 3D imaging of the internal maxillary artery using helical CT scan were done for 5 patients. These images were helpful for planning of ligation of the internal maxillary artery. (author)

  9. Helical CT imaging of clinically suspected appendicitis: Correlation of CT and histological findings

    International Nuclear Information System (INIS)

    Wong, S.K.; Chan, L.P.; Yeo, A.

    2002-01-01

    PURPOSE: The diagnosis of appendicitis is traditionally made on the basis of clinical findings supported by laboratory results. The aim of our study was to determine the accuracy and feasibility of using a relatively new technique of computed tomography (CT) using only colonic contrast medium. MATERIALS AND METHODS: A total of 50 patients clinically diagnosed as having appendicitis were prospectively examined before surgery with thin-collimation helical CT from the L3 level to the acetabular roof with only rectally administered colon contrast medium. The hard copy CT images were reviewed jointly by two radiologists and a consensus was reached for each patient. The results were then compared with the surgical and histological findings at appendicectomy. RESULTS: There were 35 true-positives, one false-positive, 12 true-negatives and two false-negatives for CT. This yielded an accuracy of 94%, sensitivity of 95%, specificity of 92%, positive predictive value of 97% and negative predictive value of 86%. The appendix was identified in 45 patients (90%) and obscured by an inflammatory mass in the remaining five. An alternative diagnosis was found in 10 of 12 normal CT examinations (83%). CONCLUSION: Helical CT with rectal contrast medium is a quick, well tolerated and accurate test to diagnose appendicitis. It can offer alternative, possibly non-surgical diagnosis in patients who would otherwise have undergone laparotomy. Wong, S.K. et al. (2002)

  10. Assessment of hepatic arterial variation using multidetector helical CT-angiography

    International Nuclear Information System (INIS)

    Lee, Dong Hoon; Lee, Jun Woo; Jun, Woong Bae; Lee, Suk Hong

    2001-01-01

    To evaluate the anatomy of the hepatic artery and normal variants using oblique thick-slab maximal intensity projection (MIP) 3-D CT angiography and multidetector helical CT technology. In 70 patients, axial three-phase CT together with multidetector helical CT and a nonionic contrast agent was used to evaluate liver disease. During the early arterial phase, the parameters were as follow: slice thickness, 2.5 mm; table speed, 15 mm/rotation, pitch, 6; contrast material, 4 ml/sec; total 120 ml. Using the MIP technique and an Advantage window voxtal 3.03 system (GE), the images obtained were reconstructed as 3D angiograms. In each case, the arterial anatomy and its variants were recorded. A typical anatomy was found in 53 cases (75.7%). Common variants were a left hepatic artery arising from the left gastric artery(8 cases, 11.4 %) and a right hepatic artery arising from the superior mesenteric artery(3 cases, 4.3%). Other variant cases were right hepatic artery arising from the gastroduodenal artery(2 cases, 2.9%), a proper hepatic artery arising from the left gastric artery (1 case, 1.4%), a hepatomesenteric trunk (1 case), a hepatogastric/splenomesenteric trunk(1 case), and a celiomesenteric trunk (1 case). 3-D hepatic angiography using multidetector helical CT technology is non-invasive and as accurate as conventional angiography for the evaluation of hepatic arterial anatomy. It is thus considered that 3-D CT angiography is very helpful for the evaluation of hepatic arterial anatomy prior to liver surgery such as transplantation or the treatment of hepatocellular carinoma

  11. CT Scan

    Science.gov (United States)

    ... disease, lung nodules and liver masses Monitor the effectiveness of certain treatments, such as cancer treatment Detect ... scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, ...

  12. Patterns of uterine enhancement with helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, H.; Loyer, E.M.; Charnsangavej, C. [Department of Diagnostic Radiology, Box 57, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Blvd. Houston, TX 77030 (United States); Minami, M. [Department of Radiology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113 (Japan)

    1998-10-01

    Objective: The purpose of this study was to evaluate the enhancement characteristics of the normal uterine body and cervix using dynamic contrast-enhanced helical CT. Methods: Thirty-eight women scheduled for pelvic CT for non-gynecologic malignancies underwent dynamic contrast-enhanced helical CT of the pelvis. Data acquisition was during the arterial phase (30-45 s after the start of injection), the parenchymal phase (90-120 s after the start of injection), and delayed phase (3-9 min after the start of injection). The images were evaluated by four radiologists for the pattern of myometrial and cervical enhancement. Correlation was made with the age and menstrual status of the patients. Results: In the uterine body, three types of enhancement were observed. Type 1 enhancement, seen in 16 patients (42%), was characterized by the visualization of a subendometrial zone of enhancement, 30-120 s after the start of injection. Eight of these patients also showed an enhancing zone in the outer myometrium. Both zones were transitory, and in all cases, the uterus became homogeneous in the delayed phase. This pattern was seen predominantly in premenopausal women with a mean age of 34 years. Type 2 enhancement, seen in 17 cases (45%), was defined by the absence of subendometrial enhancement in the early phase. Enhancement was either diffuse from the outset or originated in the outer myometrium. This pattern was seen nearly equally in premenopausal and postmenopausal women with a mean age of 40 years. Type 3 enhancement was seen in five postmenopausal patients (13%) with a mean age of 53 years and was characterized by faint diffuse enhancement. In the cervix, a zonal pattern of enhancement defining inner and outer stroma was seen in 23 patients (61%). Fifteen patients were premenopausal and eight were postmenopausal. Conclusion: In this study, we have shown a transitory zonal distribution of the contrast in the myometrium and cervix using dynamic contrast-enhanced helical CT

  13. Patterns of uterine enhancement with helical CT

    International Nuclear Information System (INIS)

    Kaur, H.; Loyer, E.M.; Charnsangavej, C.; Minami, M.

    1998-01-01

    Objective: The purpose of this study was to evaluate the enhancement characteristics of the normal uterine body and cervix using dynamic contrast-enhanced helical CT. Methods: Thirty-eight women scheduled for pelvic CT for non-gynecologic malignancies underwent dynamic contrast-enhanced helical CT of the pelvis. Data acquisition was during the arterial phase (30-45 s after the start of injection), the parenchymal phase (90-120 s after the start of injection), and delayed phase (3-9 min after the start of injection). The images were evaluated by four radiologists for the pattern of myometrial and cervical enhancement. Correlation was made with the age and menstrual status of the patients. Results: In the uterine body, three types of enhancement were observed. Type 1 enhancement, seen in 16 patients (42%), was characterized by the visualization of a subendometrial zone of enhancement, 30-120 s after the start of injection. Eight of these patients also showed an enhancing zone in the outer myometrium. Both zones were transitory, and in all cases, the uterus became homogeneous in the delayed phase. This pattern was seen predominantly in premenopausal women with a mean age of 34 years. Type 2 enhancement, seen in 17 cases (45%), was defined by the absence of subendometrial enhancement in the early phase. Enhancement was either diffuse from the outset or originated in the outer myometrium. This pattern was seen nearly equally in premenopausal and postmenopausal women with a mean age of 40 years. Type 3 enhancement was seen in five postmenopausal patients (13%) with a mean age of 53 years and was characterized by faint diffuse enhancement. In the cervix, a zonal pattern of enhancement defining inner and outer stroma was seen in 23 patients (61%). Fifteen patients were premenopausal and eight were postmenopausal. Conclusion: In this study, we have shown a transitory zonal distribution of the contrast in the myometrium and cervix using dynamic contrast-enhanced helical CT

  14. Estimation of eye lens dose during brain scans using Gafchromic XR-QA2 film in various multidetector CT scanners

    International Nuclear Information System (INIS)

    Akhilesh, Philomina; Jamhale, Shramika H.; Sharma, S.D.; Kumar, Rajesh; Datta, D.; Kulkarni, Arti R.

    2017-01-01

    The purpose of this study was to estimate eye lens dose during brain scans in 16-, 64-, 128- and 256-slice multidetector computed tomography (CT) scanners in helical acquisition mode and to test the feasibility of using radiochromic film as eye lens dosemeter during CT scanning. Eye lens dose measurements were performed using Gafchromic XR-QA2 film on a polystyrene head phantom designed with outer dimensions equivalent to the head size of a reference Indian man. The response accuracy of XR-QA2 film was validated by using thermoluminescence dosemeters. The eye lens dose measured using XR-QA2 film on head phantom for plain brain scanning in helical mode ranged from 43.8 to 45.8 mGy. The XR-QA2 film measured dose values were in agreement with TLD measured dose values within a maximum variation of 8.9%. The good correlation between the two data sets confirms the viability of using XR-QA2 film for eye lens dosimetry. (authors)

  15. Head CT scan

    Science.gov (United States)

    ... scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... head size in children Changes in thinking or behavior Fainting Headache, when you have certain other signs ...

  16. Effect of variable scanning protocolson the pre-implant site evaluation of the mandible in reformatted computed tomography

    International Nuclear Information System (INIS)

    Kim, Kee Deog; Park, Chang Seo

    1999-01-01

    To evaluate the effect of variable scanning protocols of computed tomography for evaluation of pre-implant site of the mandible through the comparison of the reformatted cross-sectional images of helical CT scans obtained with various imaging parameters versus those of conventional CT scans. A dry mandible was imaged using conventional nonoverlapped CT scans with 1 mm slice thickness and helical CT scans with 1 mm slice thickness and pitches of 1.0, 1.5, 2.0, 2.5 and 3.0. All helical images were reconstructed at reconstruction interval of 1 mm. DentaScan reformatted images were obtained to allow standardized visualization of cross-sectional images of the mandible. The reformatted images were reviewed and measured separately by 4 dental radiologists. The image qualities of continuity of cortical outline, trabecular bone structure and visibility of the mandibular canal were evaluated and the distance between anatomic structures were measured by 4 dental radiologists. On image qualities of continuity of cortical outline, trabecular bone structure and visibility of the mandibular canal and in horizontal measurement, there was no statistically significant difference among conventional and helical scans with pitches of 1.0, 1.5 and 2.0. In vertical measurement, there was no statistically significant difference among the conventional and all imaging parameters of helical CT scans with pitches of 1.0, 1.5, 2.0, 2.5 and 3.0. The images of helical CT scans with 1 mm slice thickness and pitches of 1.0, 1.5 and 2.0 are as good as those of conventional CT scans with 1 mm slice thickness for evaluation of pre-dental implant site of the mandible. Considering the radiation dose and patient comfort, helical CT scans with 1 mm slice thickness and pitch of 2.0 is recommended for evaluation of pre-implant site of the mandible.

  17. Helical 3D-CT images of soft tissue tumors in the hand

    Energy Technology Data Exchange (ETDEWEB)

    Otani, Kazuhiro; Kikuchi, Hiraku; Tan, Akihiro; Hamanishi, Chiaki; Tanaka, Seisuke [Kinki Univ., Osaka-Sayama (Japan). School of Medicine

    2000-02-01

    X-ray, ultrasonograph CT, MRI and angiography are used to detect tumoral lesions. Recently, helical CT has been revealed to be a useful method for the diagnosis and preoperative evaluation of soft tissue tumors, by which high quality and accurate three dimensional (3D) images can be obtained quickly. We analyzed the preoperative 3D-CT images of soft tissue tumors in the hands of 11 cases (hemangioma in 6 cases, giant cell tumor, lipoma, angiofibroma, chondrosarcoma and malignant fibro-histiocytoma in one case each). Enhanced 3D-CT clearly visualized hemangiomas and solid tumors from the surrounding tissues. The tumors could easily be observed from any direction and color-coded according to the CT number. Helical 3D-CT was thus confirmed to be useful for the diagnosis and preoperative planning by indicating the details of tumor expansion into surrounding tissues. (author)

  18. Optimizing radiation exposure for CT localizer radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Bohrer, Evelyn; Maeder, Ulf; Fiebich, Martin [Univ. of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection-IMPS; Schaefer, Stefan; Krombach, Gabriele A. [Univ. Hospital Giessen (Germany). Dept. of Radiology; Noel, Peter B. [Technische Univ. Muenchen (Germany). Dept. of Diagnostic and Interventional Radiology

    2017-08-01

    The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDI{sub vol} and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80 kVp, 20 mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer.

  19. Analysis of aliasing artifacts in 16-slice helical CT

    International Nuclear Information System (INIS)

    Chen Wei; Liu Jingkang; Ou Xiaoguang; Li Wenzheng; Liao Weihua; Yan Ang

    2006-01-01

    Objective: To recognize the features of aliasing artifacts on CT images, and to investigate the effects of imaging parameters on the magnitude of this artifacts. Methods: An adult dry skull was placed in a plastic water-filled container and scanned with a PHILIPS 16-slice helical CT. All the acquired transaxial images by using several different acquisition or reconstruction parameters were examined for comparative assessment of the aliasing artifacts. Results: The aliasing artifacts could be seen in most instances and characterized as the spokewise patterns emanating from the edges of high contrast structure as its radius varies sharply in the longitudinal direction. The images that scanned with pitch of 0.3, 0.6 and 0.9, respectively, showed aliasing artifacts, and its severities increased with pitches escalated (detector combination 16 x 1.5, reconstruction thickness 2 mm); There were more significant aliasing artifacts on the images reconstructed with 0.8 mm slice width compared with 1-mm slice width, and no aliasing artifacts were observed on the images reconstructed with 2-mm slice width (detector combination 16 x 0.75, pitch 0.6); No artifacts were perceived on the images scanned with detector combination 16 x 0.75, while presented evidently with the use of detector combination 16 x 1.5 (pitch 0.6, reconstruction thickness 2 mm); The degrees of aliasing artifacts were unaltered when reconstruction interval and tube current changed. Conclusions: Aliasing artifacts are caused by undersampling. When the operator choose the thinner sampling thickness, lower pitch and a much wider reconstruction thickness judiciously, aliasing artifacts could be effectively mitigated or suppressed. (authors)

  20. Angiomyolipoma with minimal fat: Differentiation from papillary renal cell carcinoma by helical CT

    International Nuclear Information System (INIS)

    Zhang, Y.-Y.; Luo, S.; Liu, Y.; Xu, R.-T.

    2013-01-01

    Aim: To evaluate whether helical computed tomography (CT) images can be used to differentiate angiomyolipomas (AMLs) with minimal fat from papillary renal cell carcinomas (PRCCs) based on their morphological characteristics and enhancement features. Materials and methods: This retrospective study was approved by the institutional review board. Informed consent was waived. Forty-four patients (21 with AMLs with minimal fat and 23 with PRCCs) who underwent enhanced helical CT before total or partial nephrectomy were included. Two radiologists, who were blinded to the histopathology results, read the CT images and recorded the attenuation value, morphological characteristics, and enhancement features of the tumours, which were subsequently evaluated. An independent samples t-test, χ 2 test, and rank sum test were performed between the tumours. The predictive value of a CT finding was determined by multivariate logistic regression analysis. Results: AML with minimal fat had an apparent female prevalence (p < 0.01). Intra-tumoural vessels were noted in 11 cases of AML with minimal fat and three PRCC cases (p < 0.01). The unenhanced attenuation characteristic was significantly different between the two diseases (p < 0.001). The absolute attenuation values (AAVs) and the corrected attenuation values (CAVs) of the AML with minimal fat group of unenhanced and two phases of enhanced images were greater compared with that of the PRCC group (p < 0.05). After contrast medium injection, the tumour enhancement value (TEV) of the AML with minimal fat group in the corticomedullary phase was greater than that of the PRCC group (p < 0.01). Most cases of both tumour types demonstrated early enhancement characteristics; the enhancement value of the AML with minimal fat group was greater compared with that of the PRCC group (p < 0.01). The unenhanced attenuation characteristic, intra-tumoural vessels, and CAVs of unenhanced and early excretory phase scans were valuable parameters to

  1. Determination of optimal parameters for three-dimensional reconstruction images of central airways using helical CT

    International Nuclear Information System (INIS)

    Hirose, Takahumi; Akata, Soichi; Matsuno, Naoto; Nagao, Takeshi; Abe, Kimihiko

    2002-01-01

    Three-dimensional (3D) image reconstruction of central airways using helical CT requires several user-defined parameters that exceed the requirements of conventional CT. The purpose of this study was to evaluate the optimal parameters for 3D images of central airways using helical CT. In our experimental study using a piglet immediately after sacrifice, 3D images of the central airway were evaluated with changes of 3D imaging parameters, such as detector collimation (1, 2, 3 and 6 mm), table speed (1, 2, 3 and 5 mm/sec), tube electric current (50, 100, 150, 200 and 250 mA), reconstruction interval (0.3, 0.5, 1, 2 and 3 mm), algorithm (mediastinum and lung) and interpolation method (180 deg and 360 deg). To minimize detector collimation, table speed, and reconstruction interval could provide the best 3D images of the central airway. Stair-step artifacts could also be reduced with a slow table speed. However, decreasing the collimation and table speed decreases not only the effective section thickness but also the scan coverage that can be achieved with a helical CT. For routine diagnosis, we conclude that optimal parameters for 3D images of the central airway are to minimize the table speed necessary to cover the volume of interest and to set detector collimation to 1/2 of the table speed. The reconstruction intervals should also be selected at up to 1/2 of the detector collimation, but with trade-offs of increased image processing time, data storage requirements, and physician time for image review. Regarding to tube electric current, 200 mA or more was necessary. Pixel noise increased with the algorithm for the lung. The 180 deg interpolation is better than 360 deg interpolation due to thin effective section thickness. (author)

  2. Estimating local noise power spectrum from a few FBP-reconstructed CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Rongping, E-mail: rongping.zeng@fda.hhs.gov; Gavrielides, Marios A.; Petrick, Nicholas; Sahiner, Berkman; Li, Qin; Myers, Kyle J. [Division of Imaging, Diagnostics, and Software Reliability, Office of Science and Engineering Laboratories, CDRH, FDA, Silver Spring, Maryland 20993 (United States)

    2016-01-15

    . Conclusions: The radial NPS method was shown to be accurate and efficient in estimating the local NPS of FBP-reconstructed 2D CT images. It presents strong advantages over traditional NPS methods when the number of scans is limited and can be extended to estimate the in-plane NPS of cone-beam CT and multislice helical CT scans.

  3. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    OpenAIRE

    Erdi Yusuf E; Casciotta Kevin A; Dauer Lawrence T; Rothenberg Lawrence N

    2007-01-01

    Abstract Background It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to...

  4. Imaging skeletal anatomy of injured cervical spine specimens: comparison of single-slice vs multi-slice helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Obenauer, S.; Alamo, L.; Herold, T.; Funke, M.; Kopka, L.; Grabbe, E. [Department of Radiology, Georg August-University Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen (Germany)

    2002-08-01

    Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT. (orig.)

  5. Multiphasic helical CT of hepatocellular carcinoma. Evaluation after chemo embolization

    International Nuclear Information System (INIS)

    Catalano, O.; Esposito, M.; Sandomenico, F.; Siani, A.; Nunziata, A.

    2000-01-01

    The main purpose of this work is to report the personal experience with addition of contrast-enhanced multiphase helical CT to unenhanced CT (Lipiodol CT) in the evaluation of patients with hepatocellular carcinoma treated with chemoembolization and to analyze the present role of oily agent CT. It has been retrospectively reviewed the examinations of 42 consecutive patients submitted to globla chemoembolization over a 2-year period. CT was performed 18-30 days after the treatment. The Lipiodol CT study was carried out with volume acquisitions. It has been considered as nodules all well-defined areas with dense oily agent uptake; uptake itself was classified as: 0=absent, I=lower tha 10% of the tumor volume; II=lower than 50%, III=50%, IV=homogeneous. Contrast-enhanced helical CT was performed with the 2-phase technique in 28 patients and with the 3-phase technique in 14; it has been considered as nodules all well-defined and relatively homogeneous areas with hyperattenuation in the arterial phase and hypo-isoattenuation in the portal and/or delayed phase, or with hypo-isoattenuation in the arterial phase and in the portal and/or delayed phase. Lipiodol CT permitted to recognize 65 nodules (1-5/patient, mean 1.5), namely 15 grade I, 21 grade II, 20 grade III and 9 grade IV. Multiphase CT identified 6 additional nodules in 5 patients, 5 hypervascular and 1 hypovascular, and better assessed the correct morphology and volume of grade I nodules. Only 4 of 6 nodules missed on Lipiodol CT showed oily agent uptake after a new chemoembolization session. Moreover after retreatment, carried out in 6 of 9 patients with grade I uptake (11 nodules in all), it has been found persistence of the grade I pattern in 5 nodules, grade II in 5, and grade III in 1. Lipiodol CT may miss liver nodules and underestimate the volume of nodules with poor uptake. Though Lipiodol CT should still be considered slightly more sensitive than multiphase CT, in the general opinion this technique has

  6. A unified analysis of FBP-based algorithms in helical cone-beam and circular cone- and fan-beam scans

    International Nuclear Information System (INIS)

    Pan Xiaochuan; Xia Dan; Zou Yu; Yu Lifeng

    2004-01-01

    A circular scanning trajectory is and will likely remain a popular choice of trajectory in computed tomography (CT) imaging because it is easy to implement and control. Filtered-backprojection (FBP)-based algorithms have been developed previously for approximate and exact reconstruction of the entire image or a region of interest within the image in circular cone-beam and fan-beam cases. Recently, we have developed a 3D FBP-based algorithm for image reconstruction on PI-line segments in a helical cone-beam scan. In this work, we demonstrated that the 3D FBP-based algorithm indeed provided a rather general formulation for image reconstruction from divergent projections (such as cone-beam and fan-beam projections). On the basis of this formulation we derived new approximate or exact algorithms for image reconstruction in circular cone-beam or fan-beam scans, which can be interpreted as special cases of the helical scan. Existing algorithms corresponding to the derived algorithms were identified. We also performed a preliminary numerical study to verify our theoretical results in each of the cases. The results in the work can readily be generalized to other non-circular trajectories

  7. The usefulness of three-dimensional helical CT for the detection of abnormalities of the auditory ossicles

    International Nuclear Information System (INIS)

    Gong, Honghan; Hiraishi, Kumiko; Uesugi, Yasuo; Shimizu, Tadafumi; Narabayashi, Isamu

    1996-01-01

    To evaluate the usefulness of three-dimensional (3D) helical CT for the detection of abnormalities of the auditory ossicles, 3D helical CT of the middle ear was performed in seven patients with hearing disorder. It revealed that 4 patients had congenital deficiency of the auditory ossicles, 2 patients with chronic otitis media had shortening of the incus and one patient with head injury had doubtful fracture of the incus. This study indicated that 3D helical CT of the middle ear can represent the auditory ossicles objectively and can offer detailed diagnosis. (author)

  8. Capability of abdominal 320-detector row CT for small vasculature assessment compared with that of 64-detector row CT

    Energy Technology Data Exchange (ETDEWEB)

    Kitajima, Kazuhiro, E-mail: kitajima@med.kobe-u.ac.jp [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Maeda, Tetsuo; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Radiology, Kobe University Hospital, Kobe (Japan); Yoshikawa, Takeshi [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Konishi, Minoru [Division of Radiology, Kobe University Hospital, Kobe (Japan); Kanda, Tomonori; Onishi, Yumiko; Matsumoto, Keiko; Koyama, Hisanobu; Takenaka, Daisuke; Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)

    2011-11-15

    Objective: To compare the capability of 320-detector row CT (area-detector CT: ADCT) with step-and-shoot scan protocol for small abdominal vasculature assessment with that of 64-detector row CT with helical scan protocol. Materials and methods: Total of 60 patients underwent contrast-enhanced abdominal CT for preoperative assessment. Of all, 30 suspected to have lung cancer underwent ADCT using step-and-shoot scan protocol. The other 30 suspected to have renal cell carcinoma underwent 64-MDCT using helical scan protocol. Two experienced radiologists independently assessed inferior epigastric, hepatic subsegmental (in the segment 8), mesenteric marginal (Griffith point) and inferior phrenic arteries by using 5-point visual scoring systems. Kappa analysis was used for evaluation of interobserver agreement. To compare the visualization capability of the two systems, the Mann-Whitney U-test was used to compare the scores for each of the arteries. Results: Overall interobserver agreements for both systems were almost perfect ({kappa} > 0.80). Visualization scores for inferior epigastric and mesenteric arteries were significantly higher for ADCT than for 64-detector row CT (p < 0.05). No significant difference was found for hepatic subsegmental and inferior phrenic arteries. Conclusion: Small abdominal vasculature assessment by ADCT with step-and-shoot scan protocol is potentially equal to or better than that by 64-detector row CT with helical scan protocol.

  9. Capability of abdominal 320-detector row CT for small vasculature assessment compared with that of 64-detector row CT

    International Nuclear Information System (INIS)

    Kitajima, Kazuhiro; Maeda, Tetsuo; Ohno, Yoshiharu; Yoshikawa, Takeshi; Konishi, Minoru; Kanda, Tomonori; Onishi, Yumiko; Matsumoto, Keiko; Koyama, Hisanobu; Takenaka, Daisuke; Sugimura, Kazuro

    2011-01-01

    Objective: To compare the capability of 320-detector row CT (area-detector CT: ADCT) with step-and-shoot scan protocol for small abdominal vasculature assessment with that of 64-detector row CT with helical scan protocol. Materials and methods: Total of 60 patients underwent contrast-enhanced abdominal CT for preoperative assessment. Of all, 30 suspected to have lung cancer underwent ADCT using step-and-shoot scan protocol. The other 30 suspected to have renal cell carcinoma underwent 64-MDCT using helical scan protocol. Two experienced radiologists independently assessed inferior epigastric, hepatic subsegmental (in the segment 8), mesenteric marginal (Griffith point) and inferior phrenic arteries by using 5-point visual scoring systems. Kappa analysis was used for evaluation of interobserver agreement. To compare the visualization capability of the two systems, the Mann-Whitney U-test was used to compare the scores for each of the arteries. Results: Overall interobserver agreements for both systems were almost perfect (κ > 0.80). Visualization scores for inferior epigastric and mesenteric arteries were significantly higher for ADCT than for 64-detector row CT (p < 0.05). No significant difference was found for hepatic subsegmental and inferior phrenic arteries. Conclusion: Small abdominal vasculature assessment by ADCT with step-and-shoot scan protocol is potentially equal to or better than that by 64-detector row CT with helical scan protocol.

  10. The sensitivity of computed tomography (CT) scans in detecting trauma: are CT scans reliable enough for courtroom testimony?

    Science.gov (United States)

    Molina, D Kimberley; Nichols, Joanna J; Dimaio, Vincent J M

    2007-09-01

    Rapid and accurate recognition of traumatic injuries is extremely important in emergency room and surgical settings. Emergency departments depend on computed tomography (CT) scans to provide rapid, accurate injury assessment. We conducted an analysis of all traumatic deaths autopsied at the Bexar County Medical Examiner's Office in which perimortem medical imaging (CT scan) was performed to assess the reliability of the CT scan in detecting trauma with sufficient accuracy for courtroom testimony. Cases were included in the study if an autopsy was conducted, a CT scan was performed within 24 hours before death, and there was no surgical intervention. Analysis was performed to assess the correlation between the autopsy and CT scan results. Sensitivity, specificity, positive predictive value, and negative predictive value were defined for the CT scan based on the autopsy results. The sensitivity of the CT scan ranged from 0% for cerebral lacerations, cervical vertebral body fractures, cardiac injury, and hollow viscus injury to 75% for liver injury. This study reveals that CT scans are an inadequate detection tool for forensic pathologists, where a definitive diagnosis is required, because they have a low level of accuracy in detecting traumatic injuries. CT scans may be adequate for clinicians in the emergency room setting, but are inadequate for courtroom testimony. If the evidence of trauma is based solely on CT scan reports, there is a high possibility of erroneous accusations, indictments, and convictions.

  11. Diagnosis of nutcracker syndrome of the left renal vein. Value of the corticomedullary phase of helical CT

    International Nuclear Information System (INIS)

    Igari, Hidenori

    2001-01-01

    The clinical significance of the corticomedullary phase of helical CT in the diagnosis of nutcracker syndrome of the left renal vein (LRV) was evaluated. A total of 38 patients with hematuria of unknown origin (12 men and 26 women, mean age 24 years [range: 18-32 years]) were examined by helical CT of the kidneys, retrograde left renal venography, and measurement of renocaval pressure gradients. The sensitivity and specificity of the corticomedullary and nephrographic phases of helical CT for detecting the nutcracker syndrome were determined. The nutcracker syndrome was diagnosed on the basis of the renography findings combined with pressure measurements in 19 patients: 12 with LRV hypertension and collateral veins, 1 with hypertension and no collateral veins, and 6 with collateral veins and normal pressure gradients or borderline hypertension. Both the corticomedullary- and nephrographic-phase images revealed distended LRVs in 26 (68%) of the 38 patients. The LRV mean attenuation values in the corticomedullary phase (164±22 Hounsfield units [H], range: 138-209 H) was significantly greater (p<0.001) than in the nephrographic phase (80±14 H, range: 62-100 H). During the corticomedullary phase, opacified blood from the renal vein was mixed with unopacified blood in the IVC. In the nephrographic phase, however, the IVC was enhanced homogeneously, but only slightly. Corticomedullary-phase imaging detected collateral veins that exhibited early enhancement, indicating retrograde flow from the LRVs in 15 out of 18 patients (83% of those with collateral veins), while the nephrographic-phase imaging revealed collateral veins in 8 patients (44% of those with collateral veins). The sensitivity and specificity of the corticomedullary-phase scan for detecting the nutcracker syndrome were 79% and 100%, respectively, as opposed to 42% and 100%, respectively, for the nephrographic phase. Retrograde flow from the LRV into the collateral veins in the corticomedullary phase is a

  12. An experimental study for qualitatively diagnosing stapes lesions by helical 3-dimensional CT

    International Nuclear Information System (INIS)

    Kawaue, Akifumi; Kuki, Kiyonori; Yamanaka, Noboru; Nishimura, Michihiko

    2001-01-01

    To evaluate qualitative diagnosis of stapes lesions by 3-dimensional computed tomography (3D-CT) combined with superselective image processing (3D-SS) of stapes, we studied helical 3D-CT on a phantom model of the temporal bone. Two stapes models were used-1 made from the bone filler, Celatite, consistent in bone density but changing in cross sectional area, and the other made from an apacerum rod used in quantitative computed tomography (QCT), consistent in cross sectional area but changing in bone density. These stapes models were put into a skull phantom and analyzed by helical 3D-CT. The influence of the tympanic cavity conditions on CT images of stapes was evaluated by filling the phantom model with Vaseline following 3D selective reconstruction. In all stapes models, lowering the lower CT window width threshold resulted in an enlarged cross-sectional area of the model. The higher the bone density, the lower the increase in cross-sectional area in the image. The stapes model with lower density had greater influence on the imaging by tympanic cavity conditions and was likely to be misdiagnosed as showing higher bone density. Based on the experimental study, 3D-SS by helical 3D-CT appears to be a useful measure for qualitatively diagnosing stapes lesions. (author)

  13. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  14. Preoperative evaluation of renal anatomy and renal masses with helical CT, 3D-CT and 3D-CT angiography.

    Science.gov (United States)

    Toprak, Uğur; Erdoğan, Aysun; Gülbay, Mutlu; Karademir, Mehmet Alp; Paşaoğlu, Eşref; Akar, Okkeş Emrah

    2005-03-01

    The aim of this prospective study was to determine the efficacy of three-dimensional computed tomography (3D-CT) and three-dimensional computed tomographic angiography (3D-CTA) that were reconstructed by using the axial images of the multiphasic helical CT in the preoperative evaluation of renal masses and demonstration of renal anatomy. Twenty patients that were suspected of having renal masses upon initial physical examination and ultrasonographic evaluation were examined through multiphasic helical CT. Two authors executed CT evaluations. Axial images were first examined and then used to reconstruct 3D-CT and 3D- CTA images. Number, location and size of the renal masses and other findings were noted. Renal vascularization and relationships of the renal masses with the neighboring renal structures were further investigated with 3D-CT and 3D-CTA images. Out of 20 patients, 13 had histopathologically proven renal cell carcinoma. The diagnoses of the remaining seven patients were xanthogranulomatous pyelonephritis, abscess, simple cyst, infected cyst, angiomyolipoma, oncocytoma and arteriovenous fistula. In the renal cell carcinoma group, 3 patients had stage I, 7 patients had stage II, and 3 patients had stage III disease. Sizes of renal cell carcinoma masses were between 23 mm to 60 mm (mean, 36 mm). Vascular invasion was shown in 2 renal cell carcinoma patients. Collecting system invasion was identified in 11 of 13 renal cell patients. These radiologic findings were confirmed with surgical specimens. Three-dimensional CT and 3D-CTA are non-invasive, effective imaging techniques for the preoperative evaluation of renal masses.

  15. Helical CT in the primary trauma evaluation of the cervical spine: an evidence-based approach

    Energy Technology Data Exchange (ETDEWEB)

    Blackmore, C.C. [Washington Univ., Seattle, WA (United States). Dept. of Radiology; Center for Cost and Outcomes Research, Univ. of Washington, Seattle (United States); Dept. of Radiology, Harborview Medical Center, Seattle, WA (United States); Mann, F.A. [Washington Univ., Seattle, WA (United States). Dept. of Radiology; Harborview Injury Prevention and Research Center, University of Washington, Seattle (United States); Wilson, A.J. [Washington Univ., Seattle, WA (United States). Dept. of Radiology

    2000-11-01

    This review provides a summary of the cost-effectiveness, clinical utility, performance, and interpretation of screening helical cervical spine CT for trauma patients. Recent evidence supports the use of helical CT as a cost-effective method for screening the cervical spine in high-risk trauma patients. Screening cervical spine CT can be performed at the time of head CT to lower the cost of the evaluation, and when all short- and long-term costs are considered, CT may actually save money when compared with traditional radiographic screening. In addition to having higher sensitivity and specificity for cervical spine injury, CT screening also allows more rapid radiological clearance of the cervical spine than radiography. Patients who are involved in high-energy trauma, who sustain head injury, or who have neurological deficits are candidates for CT screening. Screening with CT may enhance detection of other potentially important injuries of the cervical region. (orig.)

  16. Computer-aided diagnosis workstation and database system for chest diagnosis based on multi-helical CT images

    Science.gov (United States)

    Satoh, Hitoshi; Niki, Noboru; Mori, Kiyoshi; Eguchi, Kenji; Kaneko, Masahiro; Kakinuma, Ryutarou; Moriyama, Noriyuki; Ohmatsu, Hironobu; Masuda, Hideo; Machida, Suguru; Sasagawa, Michizou

    2006-03-01

    Multi-helical CT scanner advanced remarkably at the speed at which the chest CT images were acquired for mass screening. Mass screening based on multi-helical CT images requires a considerable number of images to be read. It is this time-consuming step that makes the use of helical CT for mass screening impractical at present. To overcome this problem, we have provided diagnostic assistance methods to medical screening specialists by developing a lung cancer screening algorithm that automatically detects suspected lung cancers in helical CT images and a coronary artery calcification screening algorithm that automatically detects suspected coronary artery calcification. We also have developed electronic medical recording system and prototype internet system for the community health in two or more regions by using the Virtual Private Network router and Biometric fingerprint authentication system and Biometric face authentication system for safety of medical information. Based on these diagnostic assistance methods, we have now developed a new computer-aided workstation and database that can display suspected lesions three-dimensionally in a short time. This paper describes basic studies that have been conducted to evaluate this new system. The results of this study indicate that our computer-aided diagnosis workstation and network system can increase diagnostic speed, diagnostic accuracy and safety of medical information.

  17. Maximum-intensity-projection CT angiography for evaluating head and neck tumors. Usefulness of helical CT and auto bone masking method

    International Nuclear Information System (INIS)

    Sakai, Osamu; Nakashima, Noriko; Ogawa, Chiaki; Shen, Yun; Takata, Yasunori; Azemoto, Shougo.

    1994-01-01

    Angiographic images of 10 adult patients with head and neck tumors were obtained by helical computed tomography (CT) using maximum intensity projection (MIP). In all cases, the vasculature of the head and neck region was directly demonstrated. In the head and neck, bone masking is a more important problem than in other regions. We developed an effective automatic bone masking method (ABM) using 2D/3D connectivity. Helical CT angiography with MIP and ABM provided accurate anatomic depiction, and was considered to be helpful in preoperative evaluation of head and neck tumors. (author)

  18. Spinal CT scan, 1

    International Nuclear Information System (INIS)

    Nakagawa, Hiroshi

    1982-01-01

    Methods of CT of the cervical and thoracic spines were explained, and normal CT pictures of them were described. Spinal CT was evaluated in comparison with other methods in various spinal diseases. Plain CT revealed stenosis due to spondylosis or ossification of posterior longitudinal ligament and hernia of intervertebral disc. CT took an important role in the diagnosis of spinal cord tumors with calcification and destruction of the bone. CT scan in combination with other methods was also useful for the diagnosis of spinal injuries, congenital anomalies and infections. (Ueda, J.)

  19. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    International Nuclear Information System (INIS)

    Dauer, Lawrence T; Casciotta, Kevin A; Erdi, Yusuf E; Rothenberg, Lawrence N

    2007-01-01

    It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm 3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans

  20. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans.

    Science.gov (United States)

    Dauer, Lawrence T; Casciotta, Kevin A; Erdi, Yusuf E; Rothenberg, Lawrence N

    2007-03-16

    It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0-15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

  1. Intra-arterial angio-CT for radiosurgery of cerebral arteriovenous malformations

    International Nuclear Information System (INIS)

    Tanami, Yutaka; Kunieda, Etsuo; Onozuka, Satoshi

    1998-01-01

    Intra-arterial CT-angiograms were performed for four patients undergoing stereotactic radiosurgery for cerebral arteriovenous malformations (AVM). Helical and dynamic CT scans were carried out with a scanner installed in a angiographic examination room following routine angiography. Helical scans were performed with continuous arterial infusion of contrast media. Then, dynamic scans were repeated at several table positions. Subtractions were achieved for a post-embolization case. Normal and pathological vascular structures were demonstrated with different enhancement phases with the dynamic scans. The coordinates of the target points in the nidus could be clearly determined. We concluded that intra-arterial CT-angiograms are practical and useful for treatment planning of radiosurgery for cerebral AVM. (author)

  2. Intra-arterial angio-CT for radiosurgery of cerebral arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Tanami, Yutaka; Kunieda, Etsuo; Onozuka, Satoshi [Keio Univ., Tokyo (Japan) School of Medicine] [and others

    1998-08-01

    Intra-arterial CT-angiograms were performed for four patients undergoing stereotactic radiosurgery for cerebral arteriovenous malformations (AVM). Helical and dynamic CT scans were carried out with a scanner installed in a angiographic examination room following routine angiography. Helical scans were performed with continuous arterial infusion of contrast media. Then, dynamic scans were repeated at several table positions. Subtractions were achieved for a post-embolization case. Normal and pathological vascular structures were demonstrated with different enhancement phases with the dynamic scans. The coordinates of the target points in the nidus could be clearly determined. We concluded that intra-arterial CT-angiograms are practical and useful for treatment planning of radiosurgery for cerebral AVM. (author)

  3. Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

    Directory of Open Access Journals (Sweden)

    Erdi Yusuf E

    2007-03-01

    Full Text Available Abstract Background It is estimated that 60 million computed tomography (CT scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. Methods The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. Results The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. Conclusion Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

  4. Contrast-enhanced helical CT of the pancreas. Optimal timing of imaging for pancreatic tumor evaluation

    International Nuclear Information System (INIS)

    Koide, Kazuki; Sekiguchi, Ryuzo

    2001-01-01

    We performed three-phase helical CT in patients suspected pancreatic tumors and investigated the optimal timing of imaging for evaluation of the pancreatic mass. The pancreatic-phase was superior in detecting pancreatic tumors, including islet cell tumors that may show strong enhancement. However, portal vein-phase imaging was also superior in 16.7% of our patients. Taking into account examination for hepatic metastasis, helical CT of any pancreatic tumor should include images obtained in the pancreatic and portal vein phases. (author)

  5. Evaluation of coronary artery disease by helical CT using retrospective ECG-gating

    International Nuclear Information System (INIS)

    Kawawa, Yoko

    2001-01-01

    The purpose of this study is to evaluate the usefulness of helical CT using retrospective ECG-gating for visualization of the coronary artery and detection of coronary artery disease. We performed a coronary artery phantom study and established this new application, with 1-mm collimation, 1-mm table increment, and 0.1-mm reconstruction (0.8 sec/rotation). Helical CT of 31 patients with 39 coronary artery diseases (34 coronary artery stenoses, 1 vasospastic angina, 1 coronary artery dissection, 1 coronary artery ectasia and 2 coronary artery aneurysms) was performed in a single breath hold and ECG-gating without and with intravenous injection of nonionic iodine contrast material. We selected the images which were not affected by cardiac motion from the reconstruction images, in order to visualize the coronary artery for detection of coronary artery disease. The coronary artery was well visualized in 32 out of 39 vessels (82%). A good visualization of the coronary artery was correlated with the heart rate. Further, in this well visualized group, coronary artery diseases were detected in 24 out of 31 cases (77%). One case of vasospastic angina was not included. It was difficult to detect coronary artery disease in cases of heavily calcified vessels or in the left circumflex artery. Helical CT using this retrospective ECG-gating is a useful noninvasive examination for evaluation of coronary artery disease. (author)

  6. Clinical application of helical CT 3D reconstruction for the dental orthopaedics

    International Nuclear Information System (INIS)

    Han Benyi; Jiang Xiaolu; Li Hongru

    2005-01-01

    Objective: To evaluate the clinical application of helical CT 3D reconstruction technique in the dental orthopaedics. Methods: The helical CT was performed with 3.0 mm slice thickness and 1.0 pitch in 41 patients with dental orthopaedics. The 3D reconstructions, including maximum intensity projection (MIP), surface shaded display (SSD), and multiplanar reconstructions (MPR), were made for all the cases. Results: Thirty-seven of the 41 patients showed malalignment, tilt, rotation, overlap of the teeth and the different space between the longitudinal axes of the teeth. Twenty-five cases of them have shown 36 buried teeth in all. The axial images covered all the information. SSD demonstrated the external contours and entire morphologies of the teeth and the mandible with the relationship of the teeth alignment and the mandible. MIP clearly manifested the full view and the longitudinal alignment of the teeth. Among the 36 buried teeth, there were 29 palatally and 7 labially presented teeth, and they were morphologically delineated on MIP through various angles. Conclusion: The helical CT 3D reconstruction is a new technique to display the stereoscopic configuration of teeth. The combination of axial images and MIP, SSD, and MPR provides valuable anatomic and diagnostic information helpful for the surgeons to structure and determine the treatment protocol for the dental orthopaedics. (authors)

  7. Unenhanced helical CT in the investigation of acute flank pain

    International Nuclear Information System (INIS)

    Colistro, Robert; Torreggiani, William C.; Lyburn, Iain D.; Harris, Alison C.; Al-Nakshabandi, Nizar A.; Nicolaou, Savvas; Munk, Peter L.

    2002-01-01

    Unenhanced helical CT has emerged as the imaging technique of choice for the investigation of patients presenting with acute flank pain and suspected nephroureteric stone disease. There are several signs identifiable on unenhanced CT that support a diagnosis of stone disease. However, there are many pitfalls, that may confound a correct diagnosis. Some of the common pitfalls, together with methods to avoid such occurrences, will be discussed. A review of some of the common alternative diagnoses that may mimic the symptoms of nephroureteric stone disease is illustrated. Colistro, R. et al (2002)

  8. Early appearance of SARS on chest CT scan

    International Nuclear Information System (INIS)

    Cheng Xiaoguang; Feng Suchen; Xia Guoguang; Zhao Tao; Gu Xiang; Qu Hui

    2003-01-01

    Objective: To evaluate the early appearance of SARS on chest CT scan and its role in the early diagnosis. Methods: Forty cases of SARS in keeping with the criteria of the Ministry of Health had chest CT scans within 7 days of onset of symptoms, and CR chest X-ray films were available as well. These chest X-rays and CT images were retrospectively reviewed to determine if there were any abnormalities on the images. The lesions on the chest CT images were then further analyzed in terms of the number, location, size, and density. Results: Positive abnormalities on chest CT scans were revealed in all 40 SARS cases. Positive findings on CR chest films were showed in only 25 cases, equivocal in 6, and normal in 9 cases. The main abnormalities seen on CT and X-rays were pulmonary infiltrations varied markedly in severity. 70 % cases had 1 or 2 lesions on chest CT scan, 30 % cases had 3 or more lesions. The lesions seen on chest CT scan tended to be ground-glass opacification, sometimes with consolidation which was very faint and inhomogeneous, easily missed on chest X-rays. Typically the lesions were located in the periphery of the lung, or both central and peripheral lung, but very rare in a pure central location. They were commonly in the shape of patch or ball. Conclusions: Chest CT scan is much more sensitive in detecting the lesions of the lung in SARS. The early appearance of SARS on chest CT scan is characteristic but non-specific, indicating that chest CT scan plays a very important role in the early diagnosis and differential diagnosis of SARS

  9. Pediatric CT Scans

    Science.gov (United States)

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  10. Overranging at multisection CT: an underestimated source of excess radiation exposure.

    NARCIS (Netherlands)

    Schilham, A.; Molen, A.J. van der; Prokop, M.; Jong, H.W. de

    2010-01-01

    To reconstruct the first and last sections of a helical computed tomographic (CT) scan, the scan length is automatically extended beyond the planned image boundaries, a phenomenon known as overranging. With common 16-section CT scanning protocols, the overrange length is between 3 and 6 cm. For

  11. Heart CT scan

    Science.gov (United States)

    ... make to decrease the risk of heart disease. Risks Risks of CT scans include: Being exposed to ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  12. Evaluation of residual hepatocellular carcinoma after transcatheter arterial chemoembolization: Comparison between contrast-enhanced helical CT and contrast-enhanced power doppler ultrasonography

    International Nuclear Information System (INIS)

    Kim, Seung Hoon; Lim, Hyo Keun; Lee, Won Jae

    2001-01-01

    To evaluate the effectiveness of contrast-enhanced helical CT and contrast-enhanced power doppler ultrasonography (PDUS) in assessing the therapeutic effect of transcatheter arterial chemoembolization (TACE) in hepatocellular carcinomas (HCCs). The follow-up contrast-enhanced helical CT and contrast-enhanced PDUS were performed for twenty-nine nodular HCCs from twelve patients previously treated with TACE. We defined the residual HCCs as intratumoral enhancing area on contrast-enhanced helical CT and color signal on contrast-enhanced PDUS. The interval between two examinations was less than 2 weeks (mean, 9 days). Two radiologists evaluated two examinations by consensus, and the results of these two examination were compared with the findings of other examinations including CT, angiography, and/or pathology to calculate the sensitivity, specificity and accuracy of two examinations. Of the 29 HCCs, 20 had residual HCCs whereas no residual HCCs in 9 HCCs on pathologic examination and/or follow-up radiologic study. The sensitivity, sensitivity and accuracy of contrast-enhanced helical CT were 65 (13/20), 89 (8/9), and 72% (21/29) while those of contrast-enhanced PDUS were 100 (20/20), 89 (8/9) and 97% (28/29), respectively. A microbubble contrast-enhanced PDUS was more effective in the detection of residual tumor in HCCs following TACE than contrast-enhanced helical CT.

  13. Colonic metastasis from renal cell carcinoma: helical-CT demonstration

    International Nuclear Information System (INIS)

    Diaz-Candamio, M.J.; Pombo, S.; Pombo, F.

    2000-01-01

    Clinically evident colonic metastasis from renal cell carcinoma (RCC) is rare. In the present study a hypervascular sigmoid mass was demonstrated on arterial-phase helical CT using a water enema in a patient who had suffered left nephrectomy 8 years previously for RCC. The intense and early enhancement of the lesion suggested the possibility of a solitary colonic metastasis from RCC, a diagnosis which was pathologically confirmed. (orig.)

  14. TH-E-17A-02: High-Pitch and Sparse-View Helical 4D CT Via Iterative Image Reconstruction Method Based On Tensor Framelet

    International Nuclear Information System (INIS)

    Guo, M; Nam, H; Li, R; Xing, L; Gao, H

    2014-01-01

    Purpose: 4D CT is routinely performed during radiation therapy treatment planning of thoracic and abdominal cancers. Compared with the cine mode, the helical mode is advantageous in temporal resolution. However, a low pitch (∼0.1) for 4D CT imaging is often required instead of the standard pitch (∼1) for static imaging, since standard image reconstruction based on analytic method requires the low-pitch scanning in order to satisfy the data sufficient condition when reconstructing each temporal frame individually. In comparison, the flexible iterative method enables the reconstruction of all temporal frames simultaneously, so that the image similarity among frames can be utilized to possibly perform high-pitch and sparse-view helical 4D CT imaging. The purpose of this work is to investigate such an exciting possibility for faster imaging with lower dose. Methods: A key for highpitch and sparse-view helical 4D CT imaging is the simultaneous reconstruction of all temporal frames using the prior that temporal frames are continuous along the temporal direction. In this work, such a prior is regularized through the sparsity transform based on spatiotemporal tensor framelet (TF) as a multilevel and high-order extension of total variation transform. Moreover, GPU-based fast parallel computing of X-ray transform and its adjoint together with split Bregman method is utilized for solving the 4D image reconstruction problem efficiently and accurately. Results: The simulation studies based on 4D NCAT phantoms were performed with various pitches (i.e., 0.1, 0.2, 0.5, and 1) and sparse views (i.e., 400 views per rotation instead of standard >2000 views per rotation), using 3D iterative individual reconstruction method based on 3D TF and 4D iterative simultaneous reconstruction method based on 4D TF respectively. Conclusion: The proposed TF-based simultaneous 4D image reconstruction method enables high-pitch and sparse-view helical 4D CT with lower dose and faster speed

  15. Cost-effectiveness analysis on the results of screening of lung cancer using helical CT conducted by the anti-lung cancer association (ALCA)

    International Nuclear Information System (INIS)

    Iinuma, Takeshi; Kaneko, Masahiro; Moriyama, Noriyuki; Misawa, Jun

    1999-01-01

    To compare Yen/person saved in lung cancer screening using helical CT with Yen/person in the screening using conventional direct chest X-rays conducted under the Anti-lung cancer association program of the Tokyo Health Service Association. A mathematical model for cancer screening was used to estimate net number of person relieved from lung cancer by the screening and net cost required for the screening. Finally cost-effectiveness ratios in terms of Yen/person saved were calculated and compared between the two programs. Several important variables employed in the model were as follows: 5 year survival rate in chest X-ray group was 50%, and the rate in helical CT group was 75%. Cost of screening in the chest X-ray group was 15,000 Yen, and that in the helical CT group was 25,000 Yen. Cost/person screened was 14,470 Yen for chest X-ray and 21,890 Yen for helical CT. Cost/person saved was 267 x 10 5 Yen in X-ray group and 112 x 10 5 Yen in CT group. Thus the cost was higher, but cost-effectiveness ratio was better in the CT screening group. Helical CT can be adopted for lung cancer screening in stead of chest X-ray if total cost is affordable. (author)

  16. Multislice helical CT (MSCT) for mid-facial trauma: optimization of parameters for scanning and reconstruction; Mehrschicht-Spiral-CT (MSCT) beim Mittelgesichtstrauma: Optimierung der Aufnahme- und Rekonstruktionsparameter

    Energy Technology Data Exchange (ETDEWEB)

    Dammert, S.; Funke, M.; Obernauer, S.; Grabbe, E. [Abt. Roentgendiagnostik I, Georg-August-Univ. Goettingen (Germany); Merten, H.A. [Abt. fuer Mund-, Kiefer- und Gesichtschirurgie, Georg-August-Univ. Goettingen (Germany)

    2002-07-01

    Purpose: To determine the optimal scan parameters in multislice helical CT (MSCT) of the facial bone complex for both axial scanning and multiplanar reconstructions. Material and Methods: An anthropomorphic skull phantom was examined with a MSCT. Axial scans were performed with continuously increasing collimations (4 x 1.25 - 4 x 2.5 mm), tube current (20 - 200 mA) and table speeds (3.75 mm/rot. and 7.5 mm/rot.). Multiplanar reconstructions in coronal and parasagittal planes with different reconstruction increment and slice thickness were evaluated in terms of image noise, contour artifacts and visualisation of anatomical structures. Results: The best image quality was obtained with a collimation of 4 x 1.25 mm and a - table speed of 3.75 mm/rot. A reconstruction increment of 0.6 mm achieved the best time to image quality relation. With these parameters the bone structures were depicted in an optimal way without artifacts. The tube current could be reduced to 50 mA without significant loss of image quality. The optimized protocol was used for regular routine examinations in patients with facial trauma (n = 66). Conclusions: Low-dose MSCT using thin collimation, low table speed and small reconstruction increments provides excellent data for both axial images and multiplanar reconstructions in patients with facial trauma. An additional examination in coronal orientation is therefore no longer necessary. (orig.) [German] Zielsetzung: Verbesserung der Aufnahme- und Rekonstruktionsparameter in der Mehrschicht Spiral-CT (MSCT) zur Untersuchung des knoechernen Mittelgesichtes in verschiedenen Ebenen. Material und Methode: Ein anthropomorphes Schaedel-Phantom wurde in axialer Schichtfuehrung mit einem MSCT untersucht, wobei die Kollimation (1,25 - 2,5 mm), der Tischvorschubfaktor (Pitch 3 - 6) und der Roehrenstrom (20 - 200 mA) systematisch variiert wurden. Aus den Volumendatensaetzen wurden jeweils koronare und parasagittale Sekundaerreformationen mit unterschiedlichen

  17. Prospectively ECG-triggered sequential dual-source coronary CT angiography in patients with atrial fibrillation: comparison with retrospectively ECG-gated helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Lei; Yang, Lin; Zhang, Zhaoqi [Capital Medical University, Department of Radiology, Beijing Anzhen Hospital, Beijing (China); Wang, Yining; Jin, Zhengyu [Chinese Academy of Medical Sciences, Department of Radiology, Peking Union Medical College Hospital, Beijing (China); Zhang, Longjiang; Lu, Guangming [Nanjing University, Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing, Jiangsu (China)

    2013-07-15

    To investigate the feasibility of applying prospectively ECG-triggered sequential coronary CT angiography (CCTA) to patients with atrial fibrillation (AF) and evaluate the image quality and radiation dose compared with a retrospectively ECG-gated helical protocol. 100 patients with persistent AF were enrolled. Fifty patients were randomly assigned to a prospective protocol and the other patients to a retrospective protocol using a second-generation dual-source CT (DS-CT). Image quality was evaluated using a four-point grading scale (1 = excellent, 2 = good, 3 = moderate, 4 = poor) by two reviewers on a per-segment basis. The coronary artery segments were considered non-diagnostic with a quality score of 4. The radiation dose was evaluated. Diagnostic segment rate in the prospective group was 99.4 % (642/646 segments), while that in the retrospective group was 96.5 % (604/626 segments) (P < 0.001). Effective dose was 4.29 {+-} 1.86 and 11.95 {+-} 5.34 mSv for each of the two protocols (P < 0.001), which was a 64 % reduction in the radiation dose for prospective sequential imaging compared with retrospective helical imaging. In AF patients, prospectively ECG-triggered sequential CCTA is feasible using second-generation DS-CT and can decrease >60 % radiation exposure compared with retrospectively ECG-gated helical imaging while improving diagnostic image quality. (orig.)

  18. Acute ureterolithiasis: Incidence of secondary signs on unenhanced helical CT and influence on patient management

    Energy Technology Data Exchange (ETDEWEB)

    Ege, G. E-mail: gurkanege@yahoo.com; Akman, H.; Kuzucu, K.; Yildiz, S

    2003-12-01

    AIM: The purpose of this study was to determine the incidence of secondary signs associated with ureteral stones on unenhanced helical computed tomography (CT) of patients with acute renal colic, and to correlate these with patient management and outcome. MATERIALS AND METHODS: One hundred and ten patients with ureterolithiasis were evaluated prospectively for the secondary signs of obstruction on unenhanced helical CT. Our attention was focused primarily on the presence or absence of seven secondary signs on unenhanced helical CT, including hydronephrosis, unilateral renal enlargement, perinephric oedema, unilateral absence of the white pyramid, hydroureter, periureteral oedema and lateroconal fascial thickening. RESULTS: Of the 110 patients, 91 (82.7%) had hydroureter, 88 (80%) had hydronephrosis, 65 (59%) had periureteric oedema and 63 (57.2%) had unilateral renal enlargement. Ninety stones passed spontaneously and 21 required intervention. CONCLUSION: Secondary signs of urinary tract obstruction are useful and supportive findings in interpretation of the CT examination. In our experience, the most reliable signs indicating ureteral obstruction are hydroureter, hydronephrosis, periureteral oedema and unilateral renal enlargement, respectively. In addition, stones larger than 6 mm, located within the proximal two thirds of the ureter, and seen associated with five or more the secondary signs of obstruction, are more likely to require endoscopic removal and/or lithotripsy.

  19. Helical CT finding of carotid-cavernous fistula: a sign of early enhancing superior ophthalmic vein

    International Nuclear Information System (INIS)

    Kim, Jae Hyung; Na, Dong Gyu; Byun, Hong Sik; Ryoo, Jae Wook

    2000-01-01

    The purpose of this study was to determine the diagnostic value of a sign of early enhancing superior ophthalmic vein (SOV), as seen on helical CT images in patients with carotid-cavernous fistula (CCF). This study involved 16 patients with CCF and 28 control patients. Axial CT images with scanning delays of 30 seconds following bolus injection of contrast material (90 mL, 3 mL/sec) were obtained, and this procedure was followed by coronal CT imaging. To determine the presence or absence of early enhancement or, dilatation of the SOV, bulging of the cavernous sinus, and enlargement of extraocular muscle, CT images were analysed by three observers in a blinded, random manner. Early enhancement of SOV was determined to be present where enhancement of the SOV was similar to or stronger than that of the ipsilateral posterior cerebral artery. A sign of early enhancing SOV was seen in 14 of the 16 patients with CCF but in no control patients (88% sensitivity and 100% specificity). The respective sensitivity and specificity of other CT features were 71% and 100% (dilatation of the SOV, as seen on axial images), 60% and 83% (dilatation of the SOV, as seen on coronal images), 71% and 89% (dilatation of the cavernous sinus), and 65% and 98% (enlargement of extraocular muscle). A sign of early enhancing SOV is a characteristic and specific CT finding of CCF, and is useful for the diagnosis of CCF. (author)

  20. Volume doubling time and growth rate of renal cell carcinoma determined by helical CT: a single-institution experience

    International Nuclear Information System (INIS)

    Lee, Ji Young; Kim, Chan Kyo; Choi, Dongil; Park, Byung Kwan

    2008-01-01

    The purpose of this study was to retrospectively evaluate the volume doubling time (VDT) and growth rate of renal cell carcinomas (RCC) on a serial computed tomography (CT) scan. Thirty pathologically proven RCCs were reviewed with helical CT. Each tumor underwent at least two CT scans. Tumor volume was determined using an area measuring tool and the summation-of-areas technique. Growth rate was evaluated in terms of diameter and volume changes. VDT and volume growth rate were compared in relation to several factors (initial diameter, initial volume, diameter growth rate, volume growth rate, tumor grade, tumor subtype, sex or age). Mean VDT of RCCs was 505 days. Mean diameter and volume growth rate were 0.59 cm/year and 19.1 cm 3 /year, respectively. For volume and diameter growth rate, tumors ≤4 cm showed lower rates than those >4 cm (P 0.05). Volume growth rate was moderately to strongly positively correlated with initial diameter, initial volume and diameter growth rate (P < 0.05). In conclusion, small RCCs grew at a slow rate both diametrically and volumetrically. More accurate assessment of tumor growth rate and VDT may be helpful to understand the natural history of RCC. (orig.)

  1. A trial to reduce cardiac motion artifact on HR-CT images of the lung with the use of subsecond scan and special cine reconstruction algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Fumikazu; Tsuuchi, Yasuhiko; Suzuki, Keiko; Ueno, Keiko; Yamada, Takayuki; Okawa, Tomohiko [Tokyo Women`s Medical Coll. (Japan); Yun, Shen; Horiuchi, Tetsuya; Kimura, Fumiko

    1998-05-01

    We describe our trial to reduce cardiac motion artifacts on HR-CT images caused by cardiac pulsation by combining use of subsecond CT (scan time 0.8 s) and a special cine reconstruction algorithm (cine reconstruction algorithm with 180-degree helical interpolation). Eleven to 51 HR-CT images were reconstructed with the special cine reconstruction algorithm at the pitch of 0.1 (0.08 s) from the data obtained by two to six contigious rotation scans at the same level. Images with the fewest cardiac motion artifacts were selected for evaluation. These images were compared with those reconstructed with a conventional cine reconstruction algorithm and step-by-step scan. In spite of its increased radiation exposure, technical complexity and slight degradation of spatial resolution, our method was useful in reducing cardiac motion artifacts on HR-CT images in regions adjacent to the heart. (author)

  2. Bronchial carcinoid tumor: helical CT and virtual bronchoscopy

    International Nuclear Information System (INIS)

    Diez, Eduardo; Carrascosa, Patricia; Capunay, Carlos; Spinozzi, German; Abramson, Horacio; Berna, Miguel

    2001-01-01

    The authors reported a case of a 61 years old man with recurrent neumonia of the inferior right lobe diagnosed by a chest radiography. A complementary helical CT showed an endobronquial mass on the right intermediate bronchus. Virtual bronchoscopy contributed to a better definition of this lesion, confirmed by a real bronchoscopy. The lesion was diagnosed as a carcinoid tumor by a bronchial biopsy. After surgery (sleeve resection of the tumor) the patient did not show any recurrence of his broncho-neumonic clinical features. (author)

  3. Volume-artifact reduction modality by helical CT of the anterior, middle and posterior carnial fossae. Comparison with conventional CT; Volumen-Artefakt-Reduktionstechnik mittels Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube. Vergleich mit der konventionellen kranialen CT

    Energy Technology Data Exchange (ETDEWEB)

    Dorenbeck, U.; Finkenzeller, T.; Hill, K.; Feuerbach, S.; Link, J. [Regensburg Univ. (Germany). Inst. fuer Roentgendiagnostik

    2000-04-01

    Purpose: The object of this study was to determine the extent to which a new volume-artifact reduction (VAR) modality using helical CT was able to reduce artifacts in the anterior, middle and posterior fossae in comparison with conventional CT (sequential mode). Methods: In a prospective, randomized trial, 50 patients underwent helical CT (VAR) and 50 underwent sequential CT. The results were evaluated by three radiologists; influences on image quality where scaled between 1 (no artifact) and 4 (not assessable). Eight regions of the anterior, middle and posterior fossae were evaluated. Results: On average, artifacts were scaled at 2.5 in helical CT (VAR) and 3.1 in conventional CT. Significant differences were seen at the eyeball, anterior to the petrosol bone, at the internal occipital crest, and at the level of the transverse sinus (p<0.005). Conclusions: Helical CT with the VAR modality is superior to conventional, sequential CT in the area of the anterior, middle and posterior fossae. (orig.) [German] Ziel: Das Ziel dieser Studie war herauszufinden, inwieweit ein neuer Volumen-Artefakt-Reduktionsmodus (VAR) im Spiral-CT in der vorderen, mittleren und hinteren Schaedelgrube gegenueber der Einzelschicht-CT zu einer Artefaktverringerung beitragen kann. Methoden: In einer prospektiven randomisierten Studie wurden 50 Untersuchungen mit Spiral-CT und 50 mit Einzelschicht-CT bezueglich Artefakten verglichen. Die Auswertung erfolgte durch drei Radiologen, die Bildqualitaet wurde in einer Skala zwischen 1 (kein Artefakt) und 4 (Beurteilung der Region wegen Artefakten nicht moeglich) angegeben. Acht anatomische Regionen in der vorderen, mittleren und hinteren Schaedelgrube wurden auf Beeintraechtigung durch Artefakte untersucht. Ergebnisse: Im Durchschnitt betrug die Bewertung fuer die Artefaktbeeintraechtigung beim Spiral-CT (VAR) 2,5 gegenueber 3,1 bei der Einzelschicht-CT. Der VAR-Modus ermoeglichte in der mittleren und hinteren Schaedelgrube sowie im Balbus oculi

  4. Diagnosis of gynecologic pelvic masses by CT scans

    International Nuclear Information System (INIS)

    Ito, Hisao; Kubo, Atsushi; Takagi, Yaeko; Kinoshita, Fumio; Maekawa, Akira.

    1981-01-01

    Two hundred eighty four patients with gynecologic pelvic masses were evaluated with CT scans. Of the patients, 196 had subsequent surgical determination of abnormalities and pathological proof of diagnosis was obtained. Only these 196 patients were included in this study. The CT scans could provide correct diagnosis in 113 of 114 (99%) patients with benign uterine tumor and in all (100%) patients with either serous cystadenoma or dermoid cyst. However, evaluation of mucinous cystadenoma (44%) and endometriosis cyst (37%) by CT scan has some limitations. It was difficult to differentiate mucinous cystadenoma from ovarian carcinoma, because both lesions had partial multiloculation and solid-like areas in the cyst. The CT findings of endometriosis cyst had similarity with serous cystadenoma, and 5 of 8 patients with this disease were diagnosed as serous cystadenoma. Ovarian fibroma and endometrial cancer were also not determined by CT scans. CT identified 87% of patients with ovarian cancer, while false positive rate of this disease was 38% (8/21). In 6 of 13 patients with both of leiomyoma and ovarian cyst, CT was able to demonstrate ovarian lesions that were overlooked by bimanual examinations. The role of CT scanning in our clinical practice is discussed. (author)

  5. Early clinical phase of patient's management after polytrauma using 1- and 4-slice helical CT; Fruehes klinisches Management nach Polytrauma mit 1- und 4-Schicht-Spiral-CT

    Energy Technology Data Exchange (ETDEWEB)

    Kloeppel, R.; Kahn, T. [Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Schreiter, D. [Chirurgische Intensivtherapieabteilung, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany); Dietrich, J. [Abt. Neuroradiologie der Klinik und Poliklinik fuer Diagnostische Radiologie, Universitaetsklinikum Leipzig (Germany); Josten, C. [Klinik und Poliklinik fuer Unfall- und Wiederherstellungschirurgie, Zentrum fuer Chirurgie, Universitaetsklinikum Leipzig (Germany)

    2002-07-01

    In the early clinical phase the comprehensive imaging of patients with multiple trauma using helical CT is already established. Aim of this study was to assess whether MSCT may improve the patient management and the diagnostic results.The procedure is designed as follows: after life-thretening treatment x-ray of chest and ultrasound are carried out in the emergency room. Then the patient is moved to CT. From 1998 to december 2000 241 patients were examined using a single slice helical CT (Somatom plus 4), in 2001 79 patients using a 4-slice helical CT (Somatom VZ, Siemens Med.Sol.). After CT selected radiograms of the extremities were taken.359 of 360 procedures were carried out successfully. Excluding 1 case (death during 1-sl. h CT) all relevant lesions of head, neck, and body were diagnosed. Although the patients had an injury severity score of {approx}30. The change from 1slice-helical CT to 4 slice-helical CT allowed us to reduce the stay in the CT room from 28 to 16 min. The total lethality decreased by {approx}4%.Advantages for the patient arose from the standardized examination protocol using multislice CT. If integrated in an interdisciplinary management concept, it is a good compromise between examination time, comprehensive diagnostic imaging, life-saving therapeutic procedures, and therapy planning. (orig.) [German] Die klinische Erstversorgung Polytraumatisierter schliesst inzwischen in vielen Unfallkliniken den fruehzeitigen Einsatz der Spiral-CT ein. Kann die neuerlich eingefuehrte Mehrschicht-Spiral-CT Ergebnisse und Patientenmanagement weiter verbessern?Nach lebensrettenden Sofortmassnahmen, Thoraxroentgen und Notsonographie im Schockraum erfolgte die CT: Von 1998-2000 wurden 241 Patienten mit einem 1-Schicht-Spiral-CT (Somatom plus 4) und in 2001 79 Patienten mit einem 4-Schicht-Spiral-CT (Somatom VZ, beide Siemens Med. Sol.) untersucht. Klinisch ausgewaehlte Extremitaetenaufnahmen wurden ergaenzt.359 von 360 Untersuchungen verliefen erfolgreich

  6. Impact of new technologies on dose reduction in CT

    International Nuclear Information System (INIS)

    Lee, Ting-Yim; Chhem, Rethy K.

    2010-01-01

    The introduction of slip ring technology enables helical CT scanning in the late 1980's and has rejuvenated CT's role in diagnostic imaging. Helical CT scanning has made possible whole body scanning in a single breath hold and computed tomography angiography (CTA) which has replaced invasive catheter based angiography in many cases because of its easy of operation and lesser risk to patients. However, a series of recent articles and accidents have heightened the concern of radiation risk from CT scanning. Undoubtedly, the radiation dose from CT studies, in particular, CCTA studies, are among the highest dose studies in diagnostic imaging. Nevertheless, CT has remained the workhorse of diagnostic imaging in emergent and non-emergent situations because of their ubiquitous presence in medical facilities from large academic to small regional hospitals and their round the clock accessibility due to their ease of use for both staff and patients as compared to MR scanners. The legitimate concern of radiation dose has sparked discussions on the risk vs benefit of CT scanning. It is recognized that newer CT applications, like CCTA and perfusion, will be severely curtailed unless radiation dose is reduced. This paper discusses the various hardware and software techniques developed to reduce radiation dose to patients in CT scanning. The current average effective dose of a CT study is ∼10 mSv, with the implementation of dose reduction techniques discussed herein; it is realistic to expect that the average effective dose may be decreased by 2-3 fold.

  7. CT scan of Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, T; Noguchi, S; Nishitani, H [National Sanatorium of Utano, Kyoto (Japan); Kitano, H; Ikegami, Y

    1981-04-01

    In forty-eight patients with Parkinson's disease, we examined the ventricular size and the degree of cortical atrophy which were measured by the photos of CT scan and compared them with their clinical symptoms and side effects of anti-parkinsonian drugs. The ventricular size was expressed as the ventricular ratio which is the percentage of superimposed lateral ventricular area to the white and gray matter area at the slice number 2B of CT scan photos. The degree of the cortical atrophy was expressed as the sulcal numbers which were clearly visualized at the slice number 3B or 4A of CT scan photos. We used the CT scan photos of age-matched other patients which did not show definit central nervous system abnormalities. Our findings were as follows: (1) The ventricular enlargement was observed in the parkinsonian patients who showed dementia and/or Yahr's classification grades IV or V. (2) There was no correlation between the duration of this disease and the L--dopa treatments with the ventricular size and sulcal numbers. (3) The side effects of drugs such as visual hallucination were tended to be observed in the patients who showed the ventricular enlargement. (4) There was no definite correlation between the degree of cortical atrophy with clinical symptoms and side effects of various drugs. These findings suggested that the ventricular enlargement in Parkinson's disease was an important sign of dementia and the tendency of appearance of side effects of various drugs.

  8. CT scan of Parkinson's disease

    International Nuclear Information System (INIS)

    Konishi, Tetsuro; Noguchi, Sadako; Nishitani, Hiroshi; Kitano, Haruo; Ikegami, Yoshinori.

    1981-01-01

    In forty-eight patients with Parkinson's disease, we examined the ventricular size and the degree of cortical atrophy which were measured by the photos of CT scan and compared them with their clinical symptoms and side effects of anti-parkinsonian drugs. The ventricular size was expressed as the ventricular ratio which is the percentage of superimposed lateral ventricular area to the white and gray matter area at the slice number 2B of CT scan photos. The degree of the cortical atrophy was expressed as the sulcal numbers which were clearly visualized at the slice number 3B or 4A of CT scan photos. We used the CT scan photos of age-matched other patients which did not show definit central nervous system abnormalities. Our findings were as follows: (1) The ventricular enlargement was observed in the parkinsonian patients who showed dementia and/or Yahr's classification grades IV or V. (2) There was no correlation between the duration of this disease and the L--dopa treatments with the ventricular size and sulcal numbers. (3) The side effects of drugs such as visual hallucination were tended to be observed in the patients who showed the ventricular enlargement. (4) There was no definite correlation between the degree of cortical atrophy with clinical symptoms and side effects of various drugs. These findings suggested that the ventricular enlargement in Parkinson's disease was an important sign of dementia and the tendency of appearance of side effects of various drugs. (author)

  9. Current status of multi-detector row helical CT in imaging of adult ...

    African Journals Online (AJOL)

    Current status of multi-detector row helical CT in imaging of adult acquired pancreatic diseases and assessing surgical neoplastic resectability. ... The presence of inflammation, masses, and vascular invasion was evaluated and interpreted images were obtained during each phase. Results were compared with surgery, ...

  10. Metal artifact reduction of CT scans to improve PET/CT

    NARCIS (Netherlands)

    Van Der Vos, Charlotte S.; Arens, Anne I.J.; Hamill, James J.; Hofmann, Christian; Panin, Vladimir Y.; Meeuwis, Antoi P.W.; Visser, Eric P.; De Geus-Oei, Lioe Fee

    2017-01-01

    In recent years, different metal artifact reduction methods have been developed for CT. These methods have only recently been introduced for PET/CT even though they could be beneficial for interpretation, segmentation, and quantification of the PET/CT images. In this study, phantom and patient scans

  11. Metal Artifact Reduction of CT Scans to Improve PET/CT

    NARCIS (Netherlands)

    Vos, C.S. van der; Arens, A.I.J.; Hamill, J.J.; Hofmann, C.; Panin, V.Y.; Meeuwis, A.P.W.; Visser, E.P.; Geus-Oei, L.F. de

    2017-01-01

    In recent years, different metal artifact reduction methods have been developed for CT. These methods have only recently been introduced for PET/CT even though they could be beneficial for interpretation, segmentation, and quantification of the PET/CT images. In this study, phantom and patient scans

  12. Application of low dose multi-slice helical CT in orbital trauma patients

    International Nuclear Information System (INIS)

    Yang Rui; Dai Limei; Li Jianying; Wang Fengyan; Du Guoquan

    2010-01-01

    Objective: To investigate the most appropriate low radiation dose in multi-slice CT (MSCT) scans for orbital trauma patients. Methods: Thirty trauma patients with suspected orbital fractures who underwent helical CT scans with a 64-MSCT using regular dose were selected. Noise was artificially introduced to the axial images using an image space noise addition tool to simulate 6 sets of lower dose scans with tube current of 30, 70, 100, 140, 170 and 200 mA, respectively. The lowest tube current with adequate image quality for confident diagnosis was determined based on the evaluation of the overall image quality and fracture detection on images at different dose levels. The determined lowest tube current was then validated using clinical scans. Radiation dose related parameters CTDIvol, DLP, ED were also recorded. Image quality was evaluated according to its low-density resolution, noise and structure clarity and characterized into 5-grades of excellent, good, fair, worse and worst. Rank sum test and χ 2 test were used for statistics. Results: In 30 trauma patients with regular dose of 300 mA, there were 30 cases of orbital fracture, 19 cases of intraorbital emphysema, 12 cases of ocular muscle injury and 1 case of intraorbital foreign body. These changes could still be clearly observed and correctly diagnosed when the tube current was reduced to as low as 70 mA. However, the overall image quality was mostly fair. At the simulated dose of 100 mA, the majority of images were characterized as excellent or good, and there was no statistical difference compared with that of regular dose scans (P>0.05). In the clinical evaluation for 20 orbital trauma patients with the reduced tube current of 100 m A , the majority of images were judged to be excellent (9 cases) or good (17 cases) and fair (4 cases). The radiation dose (0.29 mSv) was reduced by 70% compared with that of regular tube current of 300 mA (0.86 mSv). Conclusion: The tube current of MSCT may be used as low as

  13. ECG-triggered MDR-CT for the detection of pulmonary metastases

    International Nuclear Information System (INIS)

    Pauls, S.; Wahl, J.; Aschoff, A.J.; Brambs, H.J.; Fleiter, T.R.

    2003-01-01

    Purpose: Comparison of multidetector-row CT (MDR-CT) of the chest with and without ECG triggering for the detection of pulmonary metastases. Materials and Methods: Fifty patients with malignant tumors underwent CT of the chest. The unenhanced phase was performed with ECG-triggered MDR-CT and the contrast-enhanced phase with helical MDR-CT. The ECG-triggered and standard helical scans were interpreted in separate sessions, with the analysis determining the number and demarcation of the intrapulmonary nodules and the delineation of the mediastinal structure (rated 1 = excellent to 5 = poor). Results: ECG-MDR-CT images detected 38% more pulmonary nodules than MDR-CT. The detection rate for tumors [de

  14. Unenhanced helical CT in the evaluation of the urinary tract in children and young adults following urinary tract reconstruction: comparison with sonography

    Energy Technology Data Exchange (ETDEWEB)

    Myers, M.T.; Elder, J.S.; Sivit, C.J.; Applegate, K.E. [Dept. of Radiology, Rainbow Babies and Children' s Hospital, Cleveland, OH (United States)

    2001-03-01

    Purpose. To compare the accuracy of unenhanced, helical CT with sonography for the detection of complications of urinary tract reconstruction. Materials and methods. Forty-six kidneys in 24 patients were examined with CT and sonography. All scans were assessed for ease of renal visualization, presence of renal, ureteral, and bladder calculi, renal scars, hydronephrosis, and abdominal wall hernia. The results of both imaging modalities were independently reported. Results. CT provided excellent visualization of all 46 kidneys, while sonography provided poor visualization of 8 kidneys (17 %) (P < 0.001). CT detected calculi in 10 kidneys, 1 ureter, and 7 bladders. Sonography detected calculi in only 2 kidneys, and 2 bladders. Overall, CT detected significantly more calculi than US (18 vs 4, P = 0.01). CT detected scarring in 15 kidneys, while sonography detected scarring in 10. Hydronephrosis was detected in 6 kidneys by CT and in 8 kidneys by sonography. Three abdominal wall hernias were seen at CT that were not seen at sonography. Conclusion. CT is superior to sonography for the detection of urinary tract calculi and renal scarring. CT will demonstrate abdominal wall hernias that are unsuspected. (orig.)

  15. Usefulness of multiplanar reformatted images of multi-detector row helical CT in assessment of biliary stent patency

    International Nuclear Information System (INIS)

    Kim, Soo Jin; Kim, Suk; Kim, Chang Won; Lee, Jun Woo; Lee, Tae Hong; Choo, Ki Seok; Koo, Young Baek; Moon, Tae Yong; Lee, Suk Hong

    2004-01-01

    To evaluate the usefulness of multi-detector row helical CT (MDCT), multiplanar reformatted images for the noninvasive assessment of biliary stent patency, and for the planning for management in patients with a sele-expandable metallic stent due to malignant biliary obstruction. Among 90 consecutive patients, from August 1999 to July 2003, 26 cases in 23 patients with malignant biliary obstruction who underwent self-expandable metaIlic stent insertion in the biliary system and percutaneous transhepatic biliary drainage within 7 days after CT were enrolled in this study. On CT images, the complete and functional obstruction of the stent and the precise level of obstruction were evaluated. The presence of an enhancing intraluminal mass or wall thickening around stent was determined, and the causes of obstruction were evaluated. These findings were then compared with percutaneous transhepatic cholangiography. Multi-detector row helical CT correctly demonstrated the patency of a stent in 24 cases (92.3%). It was adequate in helping to depict the precise level of stent occlusion in 23 cases (88.5%). Multi-detector row helical CT also revealed the extent of tumor that represented as an enhancing intraluminal mass or wall thickening around the stent in 23 cases, and this was represented as complete obstruction on percutaneous transhepatic cholangiography. In the case of functional obstruction, MDCT predicted the possible cause of the obstruction. Multiplanar reformatted images of multi-detector row helical CT is a useful imaging modality for the noninvasive assessment of stent patency and the precise level of obstruction when stent obstruction is suspected in the patients with self-expandable metallic stent due to malignant biliary obstruction. It can also predict the possible cause of the obstruction and allows adequate planning for the medical management of such cases

  16. Usefulness of multiplanar reformatted images of multi-detector row helical CT in assessment of biliary stent patency

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soo Jin; Kim, Suk; Kim, Chang Won; Lee, Jun Woo; Lee, Tae Hong; Choo, Ki Seok; Koo, Young Baek; Moon, Tae Yong; Lee, Suk Hong [Pusan National Univ. Hospital, Busan (Korea, Republic of)

    2004-08-01

    To evaluate the usefulness of multi-detector row helical CT (MDCT), multiplanar reformatted images for the noninvasive assessment of biliary stent patency, and for the planning for management in patients with a sele-expandable metallic stent due to malignant biliary obstruction. Among 90 consecutive patients, from August 1999 to July 2003, 26 cases in 23 patients with malignant biliary obstruction who underwent self-expandable metaIlic stent insertion in the biliary system and percutaneous transhepatic biliary drainage within 7 days after CT were enrolled in this study. On CT images, the complete and functional obstruction of the stent and the precise level of obstruction were evaluated. The presence of an enhancing intraluminal mass or wall thickening around stent was determined, and the causes of obstruction were evaluated. These findings were then compared with percutaneous transhepatic cholangiography. Multi-detector row helical CT correctly demonstrated the patency of a stent in 24 cases (92.3%). It was adequate in helping to depict the precise level of stent occlusion in 23 cases (88.5%). Multi-detector row helical CT also revealed the extent of tumor that represented as an enhancing intraluminal mass or wall thickening around the stent in 23 cases, and this was represented as complete obstruction on percutaneous transhepatic cholangiography. In the case of functional obstruction, MDCT predicted the possible cause of the obstruction. Multiplanar reformatted images of multi-detector row helical CT is a useful imaging modality for the noninvasive assessment of stent patency and the precise level of obstruction when stent obstruction is suspected in the patients with self-expandable metallic stent due to malignant biliary obstruction. It can also predict the possible cause of the obstruction and allows adequate planning for the medical management of such cases.

  17. Diagnostic value of axial CT scan

    International Nuclear Information System (INIS)

    Kiuchi, Sousuke

    1983-01-01

    Axial CT scan was used to investigate the radiological details of the temporal bone of 33 patients with chronic otitis media, secondary cholesteatoma, sensorineural hearing loss, Meniere disease, vertigo, facial spasm, and neoplasma. The axial scans showed anatomic details of the temporal bone, and at the same time clearly demonstrated the extent of the soft-tissue masses in the middle ears, as well as the destructions of the ossicles. Bone changes of the anterior walls of the epitympanum and external auditory meatus were more clearly demonstrated than by coronary CT scan. However, the axial scan had the disadvantages in demonstrating the stapes, crista transversa, and the mastoid portion of the facial canal. (author)

  18. Low dose coronary CT angiography with 256-slice helical CT

    International Nuclear Information System (INIS)

    Zhang Xiaodong; Tang Binghang; Li Fangyun

    2011-01-01

    Objective: To compare the image quality and patient radiation dose of coronary computed tomography angiography (CCTA) received by prospectively-gated step-and-shoot (SAS) technique with those obtained by retrospectively-gated spiral ( RGS) technique on a 256-slice CT scanner. Methods: A total of 200 patients were enrolled in this study. One hundred patients underwent CCTA with SAS mode were subdivided into two groups: (1) 50 patients with an average heart rate (HR) ≤ 70 bpm were scanned with a data acquisition time window centered at the 75% of the R-R cycle (group A) and (2) 50 patients with HR > 70 bpm were scanned with the data acquisition time window centered at the 45% of the R-R cycle, including a phase tolerance of ± 5% (group B). Other 100 patients underwent CCTA with RGS mode and ECG-based tube current modulation were also subdivided into two groups: (3) 50 patients with HR ≤ 70 bpm were scanned with cardiac dose right set to phase of 75% ( group C) and (4) 50 patients with HR > 70 bpm were scanned with cardiac ose Rdight set to phases of 45% and 75% (group D). All patients were grouped in randomized order. The image quality of CCTA were evaluated using a rank scale from 1 to 4 (1: excellent; 4: non-assessable). Radiation dose of the four groups received was also estimated. The image quality between groups was compared by Mann-Whitney U test. The radiation dose between groups was compared by t test. For the 100 patients received by prospective ECG-gated CCTA, the receiver operating characteristic curve (ROC) was used to analyze the CCTA image quality and average heart rate to determine the uppercutoff of HR for obtaining diagnostic coronary images with SAS mode. A Spearman correlation analysis was also performed to analyze the correlation of HR and image quality in patients underwent CCTA with SAS mode. Results: Of 2338 coronary artery segments, excellent or good image quality (score of 1 or 2) was achieved in 96.5% (585 of 606) in group A, 77.7% (445

  19. CT scan for the diagnosis of maxillary sinus carcinoma

    International Nuclear Information System (INIS)

    Kimura, Yo; Kato, Isao; Aoyagi, Masaru; Kikuchi, Akira; Koike, Yoshio; Suzuki, Hachiro.

    1984-01-01

    A comparative study between the conventional radiological examination and the computed tomographical examination for the diagnosis of maxillary sinus carcinoma was done. CT scan has been more appreciated to detect the tumor invasion in the pterygopalatine fossa, orbit, posterior ethmoid sinus and skull base than the conventional examination. CT scan was most usefull for the determination of size and location of the tumor. The prognosis by the stage-grouping was significantly separated by the new classification with CT scan. Therefore, new TNM classification of maxillary sinus carcinoma with CT scan should be taken into account. (author)

  20. Body CT (CAT Scan)

    Science.gov (United States)

    ... a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images. These ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ...

  1. The effect of pitch in multislice spiral/helical CT

    International Nuclear Information System (INIS)

    Wang, G.; Vannier, M.W.

    2000-01-01

    The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the detector collimation, and the table increment per x-ray source rotation. The pitch in multislice spiral CT is defined as the ratio of the table increment over the detector collimation in this study. In parallel to the current framework for studying longitudinal image resolution, the central fan-beam rays of direct and opposite directions are considered, assuming a narrow cone-beam angle. Generally speaking, sampling in the Radon domain by the direct and opposite central rays is nonuniform along the longitudinal axis. Using a recently developed methodology for quantifying the sensibility of signal reconstruction from non-uniformly sampled finite points, the effect of pitch on raw data interpolation is analyzed in multislice spiral CT. Unlike single-slice spiral CT, in which image quality decreases monotonically as the pitch increases, the sensibility of raw data interpolation in multislice spiral CT increases, suggesting that image quality does not decrease monotonically in this case. The most favorable pitch can be found from the sensitivity-slice spiral CT is provided. The study on the effect of pitch using the sensitivity analysis approach reveals the fundamental characteristics of raw data interpolation in multislice spiral CT, and gives insights into interaction between pitch and image quality. These results may be valuable for design of multislice spiral CT scanners and imaging protocol optimization in clinical applications. (authors)

  2. Spatial variation of the section sensitivity profile in helical CT

    International Nuclear Information System (INIS)

    Katsuta, Shoichi; Hanai, Kouzou; Kunii, Takeo; Kimura, Haruki; Imabayashi, Wataru; Muramatsu, Yoshihisa

    1999-01-01

    The section sensitivity profile (SSP) is adequate to express the properties of helical CT images. Although SSP measurement has been performed only at the center of the imaging field, we applied it to off-center positions using a metal bead and controlled tracking technique. The experimental results indicated that SSP curves vary in the imaging field according to the relative position of the x-ray focus. The results were in agreement with computer simulations. (author)

  3. Emergencies in the retroperitoneum: assessment of spread of disease by helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Scialpi, M. E-mail: michelescialpi@libero.it; Scaglione, M.; Angelelli, G.; Lupattelli, L.; Resta, M.C.; Resta, M.; Rotondo, A

    2004-04-01

    Acute pancreatitis, leaking abdominal aortic aneurysm, and renal trauma frequently occur in the setting of patients with abdominal nontraumatic and traumatic injury; it represents the most urgent conditions that may determine the presence of fluid collections or haematoma in the retroperitoneum. Single spiral CT and multidetector-row CT (MDCT) play an important role in diagnosis of retroperitoneal emergencies, providing useful informations on the type, site, extent and management of the fluid collections. An accurate CT assessment requires the awareness of the existence of dissectable retroperitoneal fascial planes. Fluid collections or haematoma tends to escape the retroperitoneal site of origin into planes extend from the diaphragm to the pelvic floor. We assess the multicompartimental anatomy of the retroperitoneum and the pathway of spread of the most frequent retroperitoneal fluid collections or haematoma by helical CT.

  4. Preliminary evaluation of helical CT colonography in detection of colonic diseases compared with double contrast barium enema

    International Nuclear Information System (INIS)

    Zhai Xiaoli; Zhang Lei; Zhai Renyou; Li Jie; Wang Yajie; Ding Yi

    2000-01-01

    Objective: To evaluate helical CT colonography in regard to technology principles, limitations, and clinical applications. Methods: Fifty-six patients underwent volume scanning using helical CT. The diseases included adenocarcinoma 39, adenomatous polyp 3, multiple diverticular 7, mucocele of appendix 1, and normal colon 6. All cases had been compared with double contrast barium enema (DCBE), proved by histology except the 6 normal colon and the 7 multiple diverticular. All CTC images were reconstructed using shaded surface display (SSD) on workstation. Then, perspective images such as the ones from DCBE were generated via ray sum. The images could clearly demonstrate the extent and detail of the disorder by using 'CUT' software, 'revolve' function, and zoom. Results: CTC correctly demonstrated 3-5 mm diverticulum, 3 mm ulcer, and 6 mm polyps. Not only show colon straitness clearly, CTC is also very sensitive to demonstrate the stenotic end of masses. In these cases, discovery rate of CTC is 100.0%, the rate of DCBE is 88.6%; CTC is more sensitive than DCBE in cases of tumor nodules. Ray sum can show the boundary of colonic mass extending to both proximal and distal ends, its discovery rate is 62.6%. Accuracy of localization for CTC is 100.0%. Conclusion: CTC is a novel technique for detecting colonic diseases. It is a safe, accurate, and non-invasive means for detection of lesions and is an efficient complement for DCBE. Further development in CTC technique is expected in the future

  5. SU-F-J-117: Impact of Motion Artifacts On Image Quality and Accuracy of Tumor Motion Reconstruction in 4D CT-On-Rails and MV-CBCT Scans: A Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Lin, T; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2016-06-15

    Purpose: To compare and quantify respiratory motion artifacts in images from free breathing 4D-CT-on-Rails(CTOR) and those from MV-Cone-beam-CT(MVCB) and facilitate respiratory motion guided radiation therapy. Methods: 4D-CTOR: Siemens Somatom CT-on-Rails system with Anzai belt loaded with pressure sensor load cells. 4D scans were performed in helical mode, pitch 0.1, gantry rotation time 0.5s, 1.5mm slice thickness, 120kVp, 400 mAs. Normal and fast breathing (>12rpm) scanning protocols were investigated. Helical scan, AIP(average intensity projection) and MIP(maximum intensity projection) were generated from 4D-CTOR scans with amplitude sorting into 10 phases.MVCB: Siemens Artiste diamond view(1MV)MVCB was performed with 5MU thorax protocol with 60 second of full rotation.Phantom: Anzai AZ-733V respiratory phantom. The settings were set to normal and resp. modes with repetition rates at 15 rpm and 10 rpm. Surgical clips, acrylic, wooden, rubber and lung density, total six mock-ups were scanned and compared in this study.Signal-to-noise ratio(SNR), contrast-to-noise ratio(CNR) and reconstructed motion volume were compared to different respiratory setups for the mock-ups. Results: Reconstructed motion volume was compared to the real object volume for the six test mock-ups. It shows that free breathing helical in all instances underestimates the object excursions largest to −67.4% and least −6.3%. Under normal breathing settings, MIP can predict very precise motion volume with minimum 0.4% and largest −13.9%. MVCB shows underestimate of the motion volume with −1.11% minimum and −18.0% maximum. With fast breathing, AIP provides bad representation of the object motion; however, the MIP can predict the motion volume with −2.0% to −11.4% underestimate. Conclusion: Respiratory motion guided radiation therapy requires good motion recording. This study shows that regular CTOR helical scans provides bad guidance, 4D CTOR AIP cannot represent the fast breathing

  6. SU-E-I-60: The Correct Selection of Pitch and Rotation Time for Optimal CT Scanning : The Big Misconception

    International Nuclear Information System (INIS)

    Ranallo, F; Szczykutowicz, T

    2014-01-01

    Purpose: To provide correct guidance in the proper selection of pitch and rotation time for optimal CT imaging with multi-slice scanners. Methods: There exists a widespread misconception concerning the role of pitch in patient dose with modern multi-slice scanners, particularly with the use of mA modulation techniques. We investigated the relationship of pitch and rotation time to image quality, dose, and scan duration, with CT scanners from different manufacturers in a way that clarifies this misconception. This source of this misconception may concern the role of pitch in single slice CT scanners. Results: We found that the image noise and dose are generally independent of the selected effective mAs (mA*time/ pitch) with manual mA technique settings and are generally independent of the selected pitch and /or rotation time with automatic mA modulation techniques. However we did find that on certain scanners the use of a pitch just above 0.5 provided images of equal image noise at a lower dose compared to the use of a pitch just below 1.0. Conclusion: The misconception that the use of a lower pitch over-irradiates patients by wasting dose is clearly false. The use of a lower pitch provides images of equal or better image quality at the same patient dose, whether using manual mA or automatic mA modulation techniques. By decreasing the pitch and the rotation times by equal amounts, both helical and patient motion artifacts can be reduced without affecting the exam time. The use of lower helical pitch also allows better scanning of larger patients by allowing a greater scan effective mAs, if the exam time can be extended. The one caution with the use of low pitch is not related to patient dose, but to the length of the scan time if the rotation time is not set short enough. Partial Research funding from GE HealthCare

  7. Patellofemoral joint dysfunction. Combined diagnostic imaging evaluation (X-rays, 3D helical CT and MRI)

    International Nuclear Information System (INIS)

    Carrascosa, P.; Sanchez, F.; Mazzucco, J.; Capanay, C.; Carrascosa, J.

    2000-01-01

    The comprehensive study including 3D helical CT, Magnetic Resonance (MR) and X-ray exams provide a more complete diagnosis than those obtained through the conventional CT. We studied 43 patients with presumptive or certain diagnosis of patellofemoral instability. All the patients were studied by: a) Radiological pair; b) Tomography under extension and flexion, without and with contraction, using a helical CT equipment; and c) MRI STIR sequence in axial plane. The findings were classified as muscular lesion, cartilage lesion, bone and associated lesions (e.g. synovitis), statistically comparing both studies (comprehensive vs. conventional). The results allow us to accept the hypothesis that the comprehensive study provides a more complete diagnosis about the origin of the patellofemoral dysfunction. In 65% of the patients, the conventional study gave a negative result. Only in 35% of the cases the result was positive, but incomplete, showing only 35.3% of the pathological findings detected by the comprehensive study. (author)

  8. Technical evaluation of DIC helical CT and 3D image for laparoscopic cholecystectomy

    International Nuclear Information System (INIS)

    Shibuya, Kouki; Uchimura, Fumiaki; Haga, Tomo

    1995-01-01

    Recently Laparoscopic Cholecystectomy (L.C.) was widely accepted for its low invasive procedure. Before L.C., it is important to understand anatomical recognization of biliary tree. We examined DIC Helical CT before L.C., and reconstructed 3D Cholangiographic image. We evaluated physical potentiality of Helical CT using Section Sensitivity Profiles (SSP) with 5, 10 mm slice thickness on 360deg linear interpolation. And we analyzed most useful 3D image for biliary tree. Results showed the SSP depended on slice thickness (X-ray beam width) and table movement at same reconstruction spacing. The peak of SSP depended on slice thickness (X-ray beam width) and reconstruction spacing at same table movement. Clinically, it was necessary under 5 mm/rotation table movement and 5 mm thickness for acquiring volume image data. 3D Cholangiographic image reconstructed with 1 mm spacing image was useful in evaluation of relationship of anatomical biliary tree. (author)

  9. Optimization of pediatric examinations in a multislice helical CT

    International Nuclear Information System (INIS)

    Ombada, T. H. A.

    2010-12-01

    Radiological protection of pediatric patients undergoing medical imaging procedures involving ionizing radiation has always received special attention. This is due to the fact that children have higher radiation sensitivity and increased likelihood for radiation-induced cancer manifesting in many more years of their life than adults. In computed tomography (CT), such attention is more important because of the potential of relatively higher radiation doses during these procedures. Such high doses are possible with technological developments where volume scanning using faster multi-slice CT systems is now preferred to conventional CT equipment. The task of this study is to assess the optimization of paediatric doses in multi-slice CT examinations. It was carried out in Alrebat University Hospital for 31 pediatric patients, 43 examinations (27 head examination and 16 body (chest, abdomen and pelvis) examinations). Data were collected for scan parameters (kV, m As, pitch, scan length, number of slices and slice thickness) and doses displayed in monitor (CTDI v ol and DLP) for head examinations and body (chest, abdomen and pelvis) examinations. For head CT, displayed CTDI v ol ranged from 1.56 to 69.12 mGy, calculated value from 2.10 to 70.93 mGy. Displayed DLP ranged from 53 to 1817 mGy.cm, calculated from 95.30 to 1532.16 mGy. cm. For body examination, the range of displayed CTDI from 1.63 to 3.92 mGy, calculated value from 2.22 to 5.34 mGy. Displayed DLP ranged from 34 to 194 mGy.cm, for calculated from 45.89 to 161.98 mGy. cm. The calculated values are in agreement with reference study dose values although there are some high values in this study for some examinations, this variation or difference may attribute to variation in pediatric ages (9 days- 15 years), scan length and m As values. There is variation between calculated and displayed values. more optimization for CT doses is needed. (Author)

  10. Optimization of pediatric examinations in a multislice helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Ombada, T H. A. [Atomic Energy Council, Sudan Academy of Sciences (SAS), Khartoum (Sudan)

    2010-12-15

    Radiological protection of pediatric patients undergoing medical imaging procedures involving ionizing radiation has always received special attention. This is due to the fact that children have higher radiation sensitivity and increased likelihood for radiation-induced cancer manifesting in many more years of their life than adults. In computed tomography (CT), such attention is more important because of the potential of relatively higher radiation doses during these procedures. Such high doses are possible with technological developments where volume scanning using faster multi-slice CT systems is now preferred to conventional CT equipment. The task of this study is to assess the optimization of paediatric doses in multi-slice CT examinations. It was carried out in Alrebat University Hospital for 31 pediatric patients, 43 examinations (27 head examination and 16 body (chest, abdomen and pelvis) examinations). Data were collected for scan parameters (kV, m As, pitch, scan length, number of slices and slice thickness) and doses displayed in monitor (CTDI{sub v}ol and DLP) for head examinations and body (chest, abdomen and pelvis) examinations. For head CT, displayed CTDI{sub v}ol ranged from 1.56 to 69.12 mGy, calculated value from 2.10 to 70.93 mGy. Displayed DLP ranged from 53 to 1817 mGy.cm, calculated from 95.30 to 1532.16 mGy. cm. For body examination, the range of displayed CTDI from 1.63 to 3.92 mGy, calculated value from 2.22 to 5.34 mGy. Displayed DLP ranged from 34 to 194 mGy.cm, for calculated from 45.89 to 161.98 mGy. cm. The calculated values are in agreement with reference study dose values although there are some high values in this study for some examinations, this variation or difference may attribute to variation in pediatric ages (9 days- 15 years), scan length and m As values. There is variation between calculated and displayed values. more optimization for CT doses is needed. (Author)

  11. Organ dose evaluation for CT scans based on in-phantom measurements

    International Nuclear Information System (INIS)

    Liu Haikuan; Zhuo Weihai; Chen Bo; Yi Yanling; Li Dehong

    2009-01-01

    Objective: To explore the organ doses and their distributions in different projections of CT scans. Methods: The CT values were measured and the linear absorption coefficients were derived for the main organs of the anthropomorphic phantom to compare with the normal values of human beings. The radiophotoluminescent glass dosimeters were set into various tissues or organs of the phantom for mimic measurements of the organ doses undergoing the head, chest, abdomen and pelvis CT scans, respectively. Results: The tissue equivalence of the phantom used in this study was good. The brain had the largest organ dose undergoing the head CT scan. The organ doses in thyroid, breast, lung and oesophagus were relatively large in performing the chest CT scan, while the liver, stomach, colon and lung had relatively hrge organ doses in abdomen CT practice. The doses in bone surface and colon exceeded by 50 mGy in a single pelvis CT scan. Conclusions: The organ doses and their distributions largely vary with different projections of CT scans. The organ doses of colon, bone marrow,gonads and bladder are fairly large in performing pelvis CT scan, which should be paid attention in the practice. (authors)

  12. Assessment of intraocular foreign bodies by helical-CT multiplanar imaging

    International Nuclear Information System (INIS)

    Papadopoulos, A.; Fotinos, A.; Maniatis, V.; Kavadias, S.; Michaelides, A.; Avouri, M.; Kalamara, C.; Stringaris, K.

    2001-01-01

    The aim of this study was to examine the effectiveness of helical CT in the assessment of intraocular foreign bodies, evaluating two protocols with different collimation. We performed helical-CT studies in 30 patients. Fifteen patients were examined with 1.5-mm collimation and the other 15 patients with 3.0-mm collimation. All other imaging parameters were identical in both protocols. Multiplanar images were reconstructed. The examinations were reviewed for presence, localization and size of intraocular foreign bodies. We compare our results with the surgical data. We estimate the required examination time. In the first group (collimation 1.5 mm) an intraorbital foreign body was detected in 8 of 15 patients. In 3 of 8 patients an intraocular foreign body (all were metallic) was detected. In the second group (collimation 3.0 mm) an intraorbital foreign body was detected in 9 of 15 patients. In 8 of 9 patients an intraocular foreign body (all were metallic) was detected. Our results were confirmed by surgery in all cases. Examination time was 36 s in the first group and 18 s in the second group. Computed tomography should be considered the imaging modality of choice in the assessment of metallic intraocular foreign bodies and 3.0-mm collimation is optional, because of reduced examination time and radiation exposure. (orig.)

  13. Clinical and CT scan pictures of cerebral cysticercosis

    Energy Technology Data Exchange (ETDEWEB)

    Singounas, E.G.; Krassanakis, K.; Karvounis, P.C. (Evangelismos Hospital, Athens (Greece))

    1982-01-01

    The clinical presentations and CT scan pictures of four patients harbouring big cysticercus cysts are described. The value of CT scanning in detecting these cysts is emphasized, and also the fact that these cysts can behave as space-occyping lesions, which must be differentiated from other cystic formations.

  14. Utility of bolus dynamic CT for the detection of hypervascular malignant hepatic tumors. Mainly referring to the comparison with delayed phase contrast-enhanced CT

    International Nuclear Information System (INIS)

    Matsuda, Hiromichi; Abe, Kimihiko; Freeny, P.C.

    1996-01-01

    In order to analyze the usefulness of dynamic contrast-enhanced CT, 84 patients who had hepatocellular carcinoma or suspected hypervascular metastases were studied with conventional incremental dynamic CT (CID-CT) or double helical CT (DH-CT). Delayed phase contrast-enhanced CT studies were consecutively performed in all patients. Thirty-six of 84 patients had malignant hepatic neoplasms; six had hepatocellular carcinoma and 30 had metastatic tumors. At first, the detectability of hepatic lesions was evaluated with bolus dynamic CT and delayed phase CT. Dynamic CT has detected more lesions than delayed CT. Some hepatic lesions described as isodensity were missed on CID-CT. Therefore, delayed phase CT cannot be eliminated when CID-CT is performed. Secondly, hepatic lesion detectability with CID-CT was compared with that of DH-CT. DH-CT did not miss the hepatic lesions picked up by delayed phase CT and was expected to provide excellent detectability of hypervascular hepatic neoplasms. In addition, first helical CT showed most hepatic lesions as areas of obvious hyperdensity, while CID-CT did not show their correct vascularities. So-called hypervascular hepatic tumors, however, were not always hypervascular and were demonstrated as areas of iso-hypodensity even on initial helical scanning. Second helical CT was useful to detect these so-called hypervascular, but actually hypovascular lesions. In conclusion, dynamic CT was helpful in detecting hypervascular hepatic malignant neoplasms, and DH-CT was more accurate than-CID-CT for the detection of hepatic lesions and the evaluation of vascular lesion. (author)

  15. The utility of helical CT in assessing the frequency of ureterolithiasis in Saudi patients

    International Nuclear Information System (INIS)

    Al-Nakshabandi, Nizar A.; Zayed, Mohamed A.; Elsharkaway, Mohamed S.; Al-Boukai, Ahmad S.; Al-Omar, M.

    2008-01-01

    Objective was to identify 650 patients who underwent Ct for renal colic and review them for age and gender in Saudi Arabia. Scans were performed on a 16 multislice scanner. A total of 650 patients with the clinical suspicion of ureteric colic were reviewed; 220 females (33.8%) and 430 males (66.2%), with a female to male ratio of 1:2. Examinations were carried out from January 2005 to November 2006, at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia. Three hundred and ninety five patients out of 650 had stones; 2 of 395 (0.5%) had stones in the 5-15 years age group, 28 (7.%) in the 16-25 years age group, 99 (25.1%) in the 26-35 years, 106 (26.8%) in the 36-45 age group, 84 (21.9%) in the 46-55 age group, 51 (12.9%) in the 56-65 age group, and 25 (6.3%) in the above 66 years age group. The most significant finding in our study is that as the patients age increases so does the percentage of stones up to the age of 56, with a peak at age group of 26-35 where stone percentage reaches 26.8%. Unenhanced helical CT is useful for the diagnosis of ureterolithiasis. (author)

  16. Multidetector-row helical CT: analysis of time management and workflow

    Energy Technology Data Exchange (ETDEWEB)

    Roos, Justus E.; Desbiolles, Lotus M.; Willmann, Juergen K.; Weishaupt, Dominik; Marincek, Borut; Hilfiker, Paul R. [Institute of Diagnostic Radiology, University Hospital Zurich (Switzerland)

    2002-03-01

    The purpose of this study was to evaluate time management and workflow for multidetector-row helical CT (MDCT). Time for patient and data handling of at total of 580 patients were evaluated at two different time periods (December 1999, August 2000), each for the following baseline measurements: (a) change of clothes/instruction; (b) patient placement on the CT table/i.v. catheter; (c) CT planning and programming; (d) CT data acquisition; (e) CT data reconstruction; (f) CT data storage/printing. All imaging was performed on a Somatom Volume Zoom (Siemens, Erlangen, Germany). Time measurements summarized for different CT protocols revealed the following: (a) 5:01 min ({+-}2.06 min); (b) 4:36 min ({+-}2.43 min); (c) 4:11 min ({+-}2.55 min); (d) 0:43 min ({+-}0.15 min); (e) 6:59 min ({+-}2.39 min); (f) 09:51 min ({+-}3.51 min). Planning and programming was most time-consuming for CT angiography, whereas chest and abdominal CT needed only 3:26 and 3:30 min, respectively. Reconstruction time was highest for HRCT (9:22 min) and CTA (9:03 min). Data storage/printing was most time-consuming for HRCT (13:02 min), followed by combined neck-chest-abdomen examinations (12:19 min). Comparing the two time periods, during which a software update was performed, a mean time reduction of 4:31 min per patient (15%, p<0.001) was achieved. Whereas CT data acquisition time is no longer a problem with MDCT, patient management, data reconstruction, and data storage are the most time-consuming parts. Well-trained technicians, state-of-the-art workstations, and fast networking are the most important factors to improve workflow. (orig.)

  17. Metastatic tumor of the pancreas: helical CT findings

    International Nuclear Information System (INIS)

    Lee, Soon Jin; Lee, Won Jae; Lim, Hyo Keun; Kim, Seung Hoon; Kim, Kyeong Ah; Choi, Sang Hee; Jang, Hyun Jung; Lee, Ji Yeon

    2000-01-01

    To analyze the helical computed tomographic (CT) findings of distant metastatic tumors to the pancreas and to determine the differential points between these and primary pamcreatic carcinomas. We sruveyed 22 patients with metastatic tumor of the pancreas, proven on the basis of clinical and pathological findings. Seventeen patients were men, and five were women, and their ages ranged between 36 and 83 years. Their primary conditions were lung cancer (n=3D15), rectal cancer (n=3D2), melanoma of the foot, chondrosarcoma of the sacrum, cervical cancer, leiomyosarcoma of the uterus, and extragonadal choriocarcinoma of the mediastinum. We retrospectively reviewed the abdominal helical CT findings, analysing the number, location, size and attenuation of masses, as well as secondary change, which included dilatation of the pancreatic and biliary ducts and invasion of peripancreatic tissue or vessels. We also evaluated the differential findings of primary pancreatic cancer. Sixteen patients had a solitary focal mass, while in five, two masses were present. Among the 22 patients, low-density nodular masses were present in 21; in the other, in whom multiple metastasis from chondrosarcoma had occurred, there was dense calcification. The size of metastatic masses varied, ranging from 0.6 to 6 cm in diameter. The pancreatic duct proximal to the mass was dilated in ten cases, while the bile duct was dilated in six. The metastatic masses masses demonstrated no peripancreatic or vascular invasion, though they showed a discrete margin and contour bulging. Single metastasis to the pancreas was most common, and metastatic masses had a discrete margin, with contour bulging. There was no peripancreatic or vascular invasion. If the metastasis involved a single low-attenuated mass, however, with pancreatic or biliary dilatation, it was difficult to differentiate this from primary pancreatic cancer. (author)

  18. Dynamic multislice helical CT of maxillomandibular lesions. Distinction of ameloblastomas from other cystic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Tozaki, Mitsuhiro; Hayashi, Katsuhiko; Fukuda, Kunihiko [Jikei Univ., Tokyo (Japan). School of Medicine

    2001-10-01

    The purpose of this study was to evaluate the clinical usefulness of dynamic multislice helical CT in differentiating ameloblastoma from other cystic lesions in cases of maxillomandibular cystic lesions. The study included 32 patients with maxillomandibular cystic lesions (ameloblastoma [n=6], myxofibroma [n=1], odontogenic keratocyst [n=3], dentigerous cyst [n=11], radicular cyst [n=11], and paradental cyst [n=2]). Dynamic study was performed before and 30 sec, and 90 sec after intravenous contrast medium administration. CT density values and percentage of density increase were calculated at 30 and 90 sec. In five cases of ameloblastoma, a rapidly enhancing area was detected within the cystic lesions at 30 sec, while no apparent rapid enhancement was seen in the other cystic lesions. Three cysts showed gradual enhancement in the marginal area at 90 sec. Comparing ameloblastoma and other kinds of cysts, we found significant differences in the percentage of density increase at 30 sec (p<0.01) and 90 sec (p<0.05). Dynamic multislice helical CT is useful in the diagnosis of cystic lesions of the maxillomandibular region, especially in the detection of neovascularities in ameloblastoma. (author)

  19. Dynamic multislice helical CT of maxillomandibular lesions. Distinction of ameloblastomas from other cystic lesions

    International Nuclear Information System (INIS)

    Tozaki, Mitsuhiro; Hayashi, Katsuhiko; Fukuda, Kunihiko

    2001-01-01

    The purpose of this study was to evaluate the clinical usefulness of dynamic multislice helical CT in differentiating ameloblastoma from other cystic lesions in cases of maxillomandibular cystic lesions. The study included 32 patients with maxillomandibular cystic lesions (ameloblastoma [n=6], myxofibroma [n=1], odontogenic keratocyst [n=3], dentigerous cyst [n=11], radicular cyst [n=11], and paradental cyst [n=2]). Dynamic study was performed before and 30 sec, and 90 sec after intravenous contrast medium administration. CT density values and percentage of density increase were calculated at 30 and 90 sec. In five cases of ameloblastoma, a rapidly enhancing area was detected within the cystic lesions at 30 sec, while no apparent rapid enhancement was seen in the other cystic lesions. Three cysts showed gradual enhancement in the marginal area at 90 sec. Comparing ameloblastoma and other kinds of cysts, we found significant differences in the percentage of density increase at 30 sec (p<0.01) and 90 sec (p<0.05). Dynamic multislice helical CT is useful in the diagnosis of cystic lesions of the maxillomandibular region, especially in the detection of neovascularities in ameloblastoma. (author)

  20. Diagnosis of pituitary adenoma by dynamic CT scanning

    International Nuclear Information System (INIS)

    Tanabe, Sumiyoshi; Uede, Teiji; Daibo, Masahiko; Niwa, Jun; Hashi, Kazuo

    1988-01-01

    The advantage of high resolution CT in the diagnosis of pituitary microadenomas has been established, but the diagnosis becomes more difficult when the pituitary microadenoma is less than 5 mm in diameter. We have studied the usefulness of dynamic CT scans particularly for diagnosis of small microadenomas. The dynamic CT scans were performed for 61 normal pituitary glands and 68 pituitary adenomas (36 microadenomas, 32 macroadenomas) with a GECT/T 9800 scanner. Coronal sections of 1.5 mm thickness were taken at the plane just in front of the pituitary stalk of the pituitary gland. Following a bolus intra-venous injection of 40 - 60 ml of contrast media using an automatic injector, ten consecutive CT scans of 2 seconds scan time were obtained, beginning 2 seconds from the start of intravenous injection. The first seven scans were taken with an interval of 2.3 seconds, and the last three scans with an interval of 10 seconds. Then, time-density curves were obtained at the ROI which were set on the anterior pituitary gland, the vascular bed of the pituitary gland, the pituitary stalk and the area of the pituitary adenoma respectively. In a normal pituitary gland, the density increases gradually and makes an S shaped curve, then attains the maximum density value (92.3 CT number) approximately 60 seconds after the administration of contrast media. The pituitary vascular bed is located in midline on the upper surface of the pituitary gland, and shows a symmetrical square, triangular or rhomboid shape. In case of pituitary adenoma, the time-density curve makes a plateau curve and attains the maximum density value (60.1 CT number) approximately 60 seconds after the administration of contrast media. In microadenoma, the pituitary vascular bed is either deformed or compressed, showing an asymmetrical shape. (author)

  1. Helical CT angiography of renal arteries: two-years of experience

    International Nuclear Information System (INIS)

    Beregi, J.P.; Louvegny, S.; Ceugnart, L.; Willoteaux, S.; Elkohen, M.; Desmoucelle, F.; Deklunder, G.; Wattinne, L.

    1997-01-01

    To evaluate the role of helical CT angiography (CTA) in the detection of renal artery stenosis in hypertensive patients. We studied 300 hypertensive patients (50 prospectively and 250 consecutively) with CTA and arteriography (n = 118). Helical acquisition (collimation 3 mm; pitch = 1, 20 seconds acquisition time) was performed 20-45 seconds after contrast injection (300 mgl/ml; 120 ml, 4 ml/sec. Transverse axial views and 3D reconstructions were analysed (360 deg interpolation algorithm, 1 mm overlapped). In the prospective series, CTA sensibility was 100 % for main renal artery stenoses and specificity was 98.2 %; however 7/32 renal accessory arteries were not visualized. In the 300 patients studies, seventy-four stenoses were detected. There were 5 false-positive and 5 false-negative studies. Secondary hypertension was detected in 26 % of patients (including 14 cases of adrenal hyperplasia). CTA is a promising technique for the detection of renal artery stenosis in hypertensive patients. (authors)

  2. Optical-CT scanning of polymer gels

    Energy Technology Data Exchange (ETDEWEB)

    Oldham, M [Radiation Oncology Physics, Duke University Medical Center, Duke University, NC (United States)

    2004-01-01

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data.

  3. Optical-CT scanning of polymer gels

    International Nuclear Information System (INIS)

    Oldham, M

    2004-01-01

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data

  4. Clinical study of retrocaval ureter diagnosed by CT scan

    International Nuclear Information System (INIS)

    Kiriyama, Isao; Hata, Ryosuke; Amemiya, Hiroshi

    1987-01-01

    Although retrocaval ureter is relatively uncommon congenital anomaly, surgical intervention is often necessary to alleviate the clinical signs and symptoms of the patients. Vena cavography has been indispensable imaging modality for the definitive diagnosis of this anomaly. Recently, however, CT scan in addition to excretory urography (IVP) and retrograde pyelography(RP) has been utilized in many reported cases in the diagnosis of retrocaval ureter. We have experienced 3 cases of retrocaval ureter consecutively. In this paper we report these 3 cases of retrocaval ureter, in which CT scan enabled us to confirm the definitive diagnosis. We also report another case of pelviureteric stenosis that was taken for retrocaval ureter by CT scan. Causes of the misdiagnosis is discussed. In conclusion CT scan is useful diagnostic modality in the diagnosis of retrocaval ureter and this lesser invasive technique might lessen the need for vena cavography. (author)

  5. Effect of Work Improvement for Promotion of Outpatient Satisfaction on CT scan

    International Nuclear Information System (INIS)

    Han, Man Seok; Kim, Tae Hyung; Lee, Seung Youl; Lee, Myeong Goo; Jeon, Min Cheol; Cho, Jae Hwan

    2012-01-01

    Nowadays, most of the hospital serves 'one stop service' for CT scan. The patients could be taken the CT scan in the day they register for scan. On the contrary to the time convenience, patients are not satisfied with long waiting time and unkindness of staff. The objective of this study is to improve the patient's satisfaction for the CT scan, by analyzing inconvenience factors and improving the service qualities. From April 1 to August 30 in 2011, we investigated the satisfaction of patients who did examined abdomen CT scan with contrast media. We analyzed the 89 questionnaires before and after the service improvements from them. The worker's kindness, the environment of CT room and understanding about CT scan were answered by questionnaire and the waiting time of a day CT scan was drawn by medical information statistics. Also, the period before improvement was from April to June and the period after improvement was from July to September. And these questionnaire was analyzed through SPSS V. 15.0. In this study, kindness of staff, environment of CT room, intelligibility for CT scan and waiting time was explored and analyzed by SPSS V.15.0. The score of kindness was improved by 32%, satisfaction level of the environment was improved by 52.54%. The understanding level about CT scan was improved by 52.36% and the waiting time of a day CT was shortened by 21% through our service enhancement programs. Consequentially, it is considered that these efforts would contribute to increase the revenue of hospital.

  6. Effect of Work Improvement for Promotion of Outpatient Satisfaction on CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Han, Man Seok; Kim, Tae Hyung [Dept. of Radiological Science, Kangwon National University, Chuncheon (Korea, Republic of); Lee, Seung Youl; Lee, Myeong Goo; Jeon, Min Cheol [Dept. of Radiology, Chungnam National University Hospital, Daejeon (Korea, Republic of); Cho, Jae Hwan [Dept. of Radiological Science, Gyeongsan University College, Daegu (Korea, Republic of)

    2012-03-15

    Nowadays, most of the hospital serves 'one stop service' for CT scan. The patients could be taken the CT scan in the day they register for scan. On the contrary to the time convenience, patients are not satisfied with long waiting time and unkindness of staff. The objective of this study is to improve the patient's satisfaction for the CT scan, by analyzing inconvenience factors and improving the service qualities. From April 1 to August 30 in 2011, we investigated the satisfaction of patients who did examined abdomen CT scan with contrast media. We analyzed the 89 questionnaires before and after the service improvements from them. The worker's kindness, the environment of CT room and understanding about CT scan were answered by questionnaire and the waiting time of a day CT scan was drawn by medical information statistics. Also, the period before improvement was from April to June and the period after improvement was from July to September. And these questionnaire was analyzed through SPSS V. 15.0. In this study, kindness of staff, environment of CT room, intelligibility for CT scan and waiting time was explored and analyzed by SPSS V.15.0. The score of kindness was improved by 32%, satisfaction level of the environment was improved by 52.54%. The understanding level about CT scan was improved by 52.36% and the waiting time of a day CT was shortened by 21% through our service enhancement programs. Consequentially, it is considered that these efforts would contribute to increase the revenue of hospital.

  7. Incidental apical disease at CT scanning

    International Nuclear Information System (INIS)

    McLoud, T.C.; Satoh, K.; Shepard, J.O.; Moore, E.H.; Kosiuk, J.P.

    1990-01-01

    Apical caps are commonly noted on standard radiographs. This paper determines how often abnormalities in the extreme apex of the lung could be identified on CT scans obtained for other reasons. A total of 158 consecutive CT scans were reviewed prospectively. Excluded were patients with obvious upper lobe pleural or parenchymal disease. Apical abnormalities were identified in 74 (46.8%) of the 158 cases. The prevalence increased with age (19% in the 8-39-year age group and 82% in patients older than 80 years). Opacities were unilateral in 44.5% and bilateral in 55.5%. The most common abnormality was linear opacities (95%)

  8. A theoretically exact reconstruction algorithm for helical cone-beam differential phase-contrast computed tomography

    International Nuclear Information System (INIS)

    Li Jing; Sun Yi; Zhu Peiping

    2013-01-01

    Differential phase-contrast computed tomography (DPC-CT) reconstruction problems are usually solved by using parallel-, fan- or cone-beam algorithms. For rod-shaped objects, the x-ray beams cannot recover all the slices of the sample at the same time. Thus, if a rod-shaped sample is required to be reconstructed by the above algorithms, one should alternately perform translation and rotation on this sample, which leads to lower efficiency. The helical cone-beam CT may significantly improve scanning efficiency for rod-shaped objects over other algorithms. In this paper, we propose a theoretically exact filter-backprojection algorithm for helical cone-beam DPC-CT, which can be applied to reconstruct the refractive index decrement distribution of the samples directly from two-dimensional differential phase-contrast images. Numerical simulations are conducted to verify the proposed algorithm. Our work provides a potential solution for inspecting the rod-shaped samples using DPC-CT, which may be applicable with the evolution of DPC-CT equipments. (paper)

  9. Volumetric measurement of the maxillary sinus by coronal CT scan

    International Nuclear Information System (INIS)

    Ikeda, Atsuko

    1996-01-01

    The volume of the maxillary sinus was estimated by coronal CT scan. The purpose of this study was to compare the estimated volume of the normal maxillary sinus with that of the inflamed maxillary sinus. Patients were classified following evaluation by CT scan of the paranasal sinuses into 3 categories. Group A (n=12): Patients suffered from headache, facial pain and epistaxis, but CT scans of their nasal cavity and paranasal sinus were within normal limits without inflammatory change. Group B (n=69): Patients with bilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory changes in both maxillary sinuses. All of the patients in this group underwent sinus surgery after coronal CT scans. Group C (n=14): Patients with unilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory change in unilateral maxillary sinuses. CT scans of these patients were measured by Plannimeter to take the area of each image of the maxillary sinus. Consecutively imaged areas were summated by integral calculus to obtain an estimate of the sinus volume. The mean maxillary sinus volume in the affected sinuses was significantly smaller than those in the contralateral normal sinuses (p<0.05, Wilcoxon-test). The various volumes of the maxillary sinuses and the developmental cause were discussed. Comparison of groups A with B suggested three distinct patterns; the maxillary sinus volume has decreased due to inflammatory changes in the bone. The small sinuses have a tendency to develop chronic inflammatory change. The aeration in the maxillary sinus may be decreased when anatomic variations that may obstruct the ethmoid infundibulum exist. (K.H.)

  10. Volumetric measurement of the maxillary sinus by coronal CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Atsuko [Tokyo Medical and Dental Univ. (Japan). School of Medicine

    1996-08-01

    The volume of the maxillary sinus was estimated by coronal CT scan. The purpose of this study was to compare the estimated volume of the normal maxillary sinus with that of the inflamed maxillary sinus. Patients were classified following evaluation by CT scan of the paranasal sinuses into 3 categories. Group A (n=12): Patients suffered from headache, facial pain and epistaxis, but CT scans of their nasal cavity and paranasal sinus were within normal limits without inflammatory change. Group B (n=69): Patients with bilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory changes in both maxillary sinuses. All of the patients in this group underwent sinus surgery after coronal CT scans. Group C (n=14): Patients with unilateral chronic maxillary sinusitis, CT scans of whom showed inflammatory change in unilateral maxillary sinuses. CT scans of these patients were measured by Plannimeter to take the area of each image of the maxillary sinus. Consecutively imaged areas were summated by integral calculus to obtain an estimate of the sinus volume. The mean maxillary sinus volume in the affected sinuses was significantly smaller than those in the contralateral normal sinuses (p<0.05, Wilcoxon-test). The various volumes of the maxillary sinuses and the developmental cause were discussed. Comparison of groups A with B suggested three distinct patterns; the maxillary sinus volume has decreased due to inflammatory changes in the bone. The small sinuses have a tendency to develop chronic inflammatory change. The aeration in the maxillary sinus may be decreased when anatomic variations that may obstruct the ethmoid infundibulum exist. (K.H.)

  11. The helical three-dimensional CT in the diagnosis of torticollis with occipitocondylar hypoplasia

    International Nuclear Information System (INIS)

    Ilkko, E.; Tikkakoski, T.; Pyhtinen, J.

    1998-01-01

    Congenital anomalies of the atlanto-occipital and atlantoaxial joints are rare. Those most commonly reported are atlantoaxial instability, basilar impression, anomalies of the odontoid process, laxity of the transverse atlantal ligament and atlanto-occipital fusion. Occipital condylar hypoplasia is infrequent and difficult to recognise. We recently diagnosed it using helical 3D CT in association with torticollis in two patients. The first patient had a several year history of torticollis. The second patient had acute cervical lymphadenitis associated with post-operative torticollis. 3D CT distinctly revealed atlantoaxial subluxation with hypoplasia of the occipital condyles in both cases

  12. SU-E-I-93: Improved Imaging Quality for Multislice Helical CT Via Sparsity Regularized Iterative Image Reconstruction Method Based On Tensor Framelet

    International Nuclear Information System (INIS)

    Nam, H; Guo, M; Lee, K; Li, R; Xing, L; Gao, H

    2014-01-01

    Purpose: Inspired by compressive sensing, sparsity regularized iterative reconstruction method has been extensively studied. However, its utility pertinent to multislice helical 4D CT for radiotherapy with respect to imaging quality, dose, and time has not been thoroughly addressed. As the beginning of such an investigation, this work carries out the initial comparison of reconstructed imaging quality between sparsity regularized iterative method and analytic method through static phantom studies using a state-of-art 128-channel multi-slice Siemens helical CT scanner. Methods: In our iterative method, tensor framelet (TF) is chosen as the regularization method for its superior performance from total variation regularization in terms of reduced piecewise-constant artifacts and improved imaging quality that has been demonstrated in our prior work. On the other hand, X-ray transforms and its adjoints are computed on-the-fly through GPU implementation using our previous developed fast parallel algorithms with O(1) complexity per computing thread. For comparison, both FDK (approximate analytic method) and Katsevich algorithm (exact analytic method) are used for multislice helical CT image reconstruction. Results: The phantom experimental data with different imaging doses were acquired using a state-of-art 128-channel multi-slice Siemens helical CT scanner. The reconstructed image quality was compared between TF-based iterative method, FDK and Katsevich algorithm with the quantitative analysis for characterizing signal-to-noise ratio, image contrast, and spatial resolution of high-contrast and low-contrast objects. Conclusion: The experimental results suggest that our tensor framelet regularized iterative reconstruction algorithm improves the helical CT imaging quality from FDK and Katsevich algorithm for static experimental phantom studies that have been performed

  13. Serial CT scannings in herpes simplex encephalitis

    International Nuclear Information System (INIS)

    Fukushima, Masashi; Sawada, Tohru; Kuriyama, Yoshihiro; Kinugawa, Hidekazu; Yamaguchi, Takenori

    1981-01-01

    Two patients with serologically confirmed herpes simplex encephalitis were studied by serial CT scannings. Case 1, a 60-year-old woman, was admitted to National Cardiovascular Center because of headache, fever, and attacks of Jacksonian seizure. Case 2, a 54-year-old man, was admitted because of fever, consciousness disturbance and right hemipare sis. Pleocytosis (mainly lymphocytes) and elevation of protein content in cerebrospinal fluid were observed in both cases. Both patients presented ''das apallische Syndrom'' one month after admission. The diagnosis of herpes simplex encephalitis was confirmed by typical clinical courses and by greater than fourfold rises in serum antibody titer for herpes simplex virus as well as that in cerebrospinal fluid in case 1. Characteristic CT findings observed in these two cases were summarized as follows: Within a week after the onset, no obvious abnormalities could be detected on CT scans (Case 1). Two weeks after the onset, a large low-density area appeared in the left temporal lobe and in the contralateral insular cortex with midline shift toward the right side (Case 2). One month later, an ill-defined linear and ring-like high-density area (Case 1), or a well-defined high-density area (Case 2), that was enhanced after contrast administration, was observed in the large low-density area in the temporal lobe. These findings were considered as characteristic for hemorrhagic encephalitis. These high-density areas disappeared two months later, however, widespread and intensified low-density areas still remained. In both cases, the basal ganglia and thalamus were completely spared on CT scans. From these observations, it can be concluded that serial CT scannings are quite useful for diagnosis of herpes simplex encephalitis. (author)

  14. Immediate total-body CT scanning versus conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomised controlled trial.

    Science.gov (United States)

    Sierink, Joanne C; Treskes, Kaij; Edwards, Michael J R; Beuker, Benn J A; den Hartog, Dennis; Hohmann, Joachim; Dijkgraaf, Marcel G W; Luitse, Jan S K; Beenen, Ludo F M; Hollmann, Markus W; Goslings, J Carel

    2016-08-13

    Published work suggests a survival benefit for patients with trauma who undergo total-body CT scanning during the initial trauma assessment; however, level 1 evidence is absent. We aimed to assess the effect of total-body CT scanning compared with the standard work-up on in-hospital mortality in patients with trauma. We undertook an international, multicentre, randomised controlled trial at four hospitals in the Netherlands and one in Switzerland. Patients aged 18 years or older with trauma with compromised vital parameters, clinical suspicion of life-threatening injuries, or severe injury were randomly assigned (1:1) by ALEA randomisation to immediate total-body CT scanning or to a standard work-up with conventional imaging supplemented with selective CT scanning. Neither doctors nor patients were masked to treatment allocation. The primary endpoint was in-hospital mortality, analysed in the intention-to-treat population and in subgroups of patients with polytrauma and those with traumatic brain injury. The χ(2) test was used to assess differences in mortality. This trial is registered with ClinicalTrials.gov, number NCT01523626. Between April 22, 2011, and Jan 1, 2014, 5475 patients were assessed for eligibility, 1403 of whom were randomly assigned: 702 to immediate total-body CT scanning and 701 to the standard work-up. 541 patients in the immediate total-body CT scanning group and 542 in the standard work-up group were included in the primary analysis. In-hospital mortality did not differ between groups (total-body CT 86 [16%] of 541 vs standard work-up 85 [16%] of 542; p=0.92). In-hospital mortality also did not differ between groups in subgroup analyses in patients with polytrauma (total-body CT 81 [22%] of 362 vs standard work-up 82 [25%] of 331; p=0.46) and traumatic brain injury (68 [38%] of 178 vs 66 [44%] of 151; p=0.31). Three serious adverse events were reported in patients in the total-body CT group (1%), one in the standard work-up group (<1%), and

  15. Evaluation of delayed contrast-enhanced CT scan in diagnosing hilar cholangiocarcinoma

    International Nuclear Information System (INIS)

    Li Jianding; Liang Chenyang; Zhang Hua; Zhang Yuezhen; Li Rui

    2001-01-01

    Objective: To assess the diagnostic value of delayed CT contrast enhancement patterns in hilar cholangiocarcinoma based on two-phased dynamic incremental CT scanning. Methods: Fifty-two patients with suspected hilar tumor and bile duct obstruction underwent spiral CT scan. The scan time for one revolution of the X-ray tube was 1 second. To elucidate the delay time for optimal imaging, all proved cholangiocarcinoma with delayed (6, 8, 10, 15, 20, 30 minutes) post-equilibrium-phase contrast-enhanced CT scans were acquired with unenhanced, dynamic contrast-enhanced, and delayed images. Degree of delayed enhancement was compared with that of surrounding liver parenchyma. Results: (1) 8-15 minutes after IV injection of contrast material was the delay time for optimal imaging. (2) Of 29 cholangiocarcinomas, the early CT showed hypo-attenuating (lower than that of liver parenchyma) in 23 tumors, iso-attenuating (equal to that of the liver) in 4 tumors, and hyper-attenuating (higher than that of liver) in 2 tumors. The delayed CT scan showed iso-attenuating in 8 tumors, hyper-attenuating in 21 tumors, and no hypo-attenuating. Most of delay imaging of hilar cholangiocarcinoma may appear hyper-attenuating (U = -4.3073, P 2 = 9.09, P < 0.01). Conclusion: When assessing hilar tumor, delayed CT contrast enhancement patterns based on two-phase dynamic incremental CT scans is useful in the detection and characterization of hilar cholangiocarcinoma

  16. Ocular volume measured by CT scans

    International Nuclear Information System (INIS)

    Hahn, F.J.; Wei-Kom Chu

    1984-01-01

    Newer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia. (orig.)

  17. Prospective comparison of helical CT with angiography in pulmonary embolism: global and selective vascular territory analysis. Interobserver agreement

    International Nuclear Information System (INIS)

    Ruiz, Yolanda; Caballero, Paloma; Caniego, Jose Luis; Friera, Alfonsa; Olivera, Maria Jose; Tagarro, David; Alvarez-Sala, Rodolfo

    2003-01-01

    The objective of this prospective study was to evaluate the sensitivity, specificity, positive and negative predictive values, and interobserver agreement in the diagnosis of pulmonary embolism with helical CT, compared with pulmonary angiography, for both global results and for selective vascular territories. Helical CT and pulmonary angiography were performed on 66 consecutive patients with clinical suspicion of pulmonary embolism. The exams were blindly interpreted by a vascular radiologist and by two independent thoracic radiologists. Results were analyzed for the final diagnosis as well as separately for 20 different arterial territories in each patient. Pulmonary angiography revealed embolism in 25 patients (38%); 48% were main, 28% lobar, 16% segmental, and 8% subsegmental. The sensitivity, specificity, and positive and negative predictive values of helical CT for observer 1 were, respectively, 91, 81.5, 75, and 94%; in 7.5% of the patients the exam was considered indeterminate. For observer 2 the values were, respectively, 88, 86, 81.5, and 91%; in 9% of the patients the exam was considered indeterminate. Main arteries were considered as non-valuable in 0-0.8%, the lobar in 1.5%, the segmental in 7.5-8.5%, and the subsegmental in 55-60%. Interobserver agreement for the final diagnosis was 80% (kappa 0.65). For each vascular territory, this was 98% (kappa 0.91) for main arteries, 92% (kappa 0.78) for lobar arteries, 79% (kappa 0.56) for segmental arteries, and 59% (kappa 0.21) for subsegmental arteries. Helical CT is a reliable method for pulmonary embolism diagnosis, with good interobserver agreement for main, lobar, and segmental territories. Worse results are found for subsegmental arteries, with high incidence of non-valuable branches and poor interobserver agreement. (orig.)

  18. Immediate total-body CT scanning versus conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomised controlled trial

    NARCIS (Netherlands)

    Sierink, Joanne C.; Treskes, Kaij; Edwards, Michael J. R.; Beuker, Benn J. A.; den Hartog, Dennis; Hohmann, Joachim; Dijkgraaf, Marcel G. W.; Luitse, Jan S. K.; Beenen, Ludo F. M.; Hollmann, Markus W.; Goslings, J. Carel; Saltzherr, T. P.; Schep, N. W. L.; Streekstra, G. J.; van Lieshout, E. M. M.; Patka, P.; Klimek, M.; van Vugt, R.; Tromp, T. J. N.; Brink, M.; Harbers, J. S.; El Moumni, M.; Wendt, K. W.; Bingisser, R.; Ummenhofer, W.; Bless, N.

    2016-01-01

    Published work suggests a survival benefit for patients with trauma who undergo total-body CT scanning during the initial trauma assessment; however, level 1 evidence is absent. We aimed to assess the effect of total-body CT scanning compared with the standard work-up on in-hospital mortality in

  19. Dual scan CT image recovery from truncated projections

    Science.gov (United States)

    Sarkar, Shubhabrata; Wahi, Pankaj; Munshi, Prabhat

    2017-12-01

    There are computerized tomography (CT) scanners available commercially for imaging small objects and they are often categorized as mini-CT X-ray machines. One major limitation of these machines is their inability to scan large objects with good image quality because of the truncation of projection data. An algorithm is proposed in this work which enables such machines to scan large objects while maintaining the quality of the recovered image.

  20. Delayed intracerebral hemorrhage as demonstrated by CT scanning

    International Nuclear Information System (INIS)

    Brunetti, J.; Zingesser, L.; Dunn, J.; Rovit, R.L.; Saint Vincent's Hospital and Medical Center, New York

    1979-01-01

    Three patients are presented who developed delayed intracerebral hematomas after head injury. Two patients had essentially negative CT scans on admission and developed intracerebral hematomas within 24 h after injury. They required surgical treatment and had fatal outcomes. The third patient presented with an epidural hematoma on CT scan, developed an intracerebral hematoma 48 h after evacuation of the epidural hematoma, and did well with conservative management. (orig.) [de

  1. Hepatic parenchymal perfusion abnormalities after pancreaticobiliary surgery. Evaluation with dynamic helical CT

    International Nuclear Information System (INIS)

    Mitsuzaki, K.; Yamashita, Y.; Ogata, I.; Nishiharu, T.; Urata, J.; Takahashi, M.

    1998-01-01

    Purpose: To evaluate perfusion abnormalities of the liver after pancreaticobiliary surgery. Material and Methods: We retrospectively evaluated 128 patients with pancreaticobiliary malignant tumors who had been examined both before and after surgery by means of helical CT of the liver. An infusion of 3 ml/s of 60% nonionic contrast material was followed by helical CT of the liver in a sequential arterial phase, portal venous phase, and equilibrium phase. Results: Of 128 patients, we followed 97. In 21 patients (22%) we found 47 lesions with perfusion abnormalities that were detected 1-33 months (mean 6.6 months) after the operation. All patients were asymptomatic. The shape of each perfusion abnormality was characterized as geographic (n=23, 47%), wedge-shaped (n=21, 45%), or round (n=3, 8%). The abnormalities were seen in the arterial phase in 46 lesions (98%), in the portal venous phase in 18 lesions (38%), and in the equilibrium phase in 1 lesion (0.2%). In all lesions, the size either decreased spontaneously, or it remained unchanged for more than one year. Conclusion: Perfusion abnormalities of the liver may occur in patients who undergo pancreaticobiliary surgery. These findings should not be confused with hypervascular metastases. (orig.)

  2. Hepatic parenchymal perfusion abnormalities after pancreaticobiliary surgery. Evaluation with dynamic helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuzaki, K.; Yamashita, Y.; Ogata, I.; Nishiharu, T.; Urata, J.; Takahashi, M. [Kumamoto Univ., School of Medicine, Dept. of Radiology (Japan)

    1998-05-01

    Purpose: To evaluate perfusion abnormalities of the liver after pancreaticobiliary surgery. Material and Methods: We retrospectively evaluated 128 patients with pancreaticobiliary malignant tumors who had been examined both before and after surgery by means of helical CT of the liver. An infusion of 3 ml/s of 60% nonionic contrast material was followed by helical CT of the liver in a sequential arterial phase, portal venous phase, and equilibrium phase. Results: Of 128 patients, we followed 97. In 21 patients (22%) we found 47 lesions with perfusion abnormalities that were detected 1-33 months (mean 6.6 months) after the operation. All patients were asymptomatic. The shape of each perfusion abnormality was characterized as geographic (n=23, 47%), wedge-shaped (n=21, 45%), or round (n=3, 8%). The abnormalities were seen in the arterial phase in 46 lesions (98%), in the portal venous phase in 18 lesions (38%), and in the equilibrium phase in 1 lesion (0.2%). In all lesions, the size either decreased spontaneously, or it remained unchanged for more than one year. Conclusion: Perfusion abnormalities of the liver may occur in patients who undergo pancreaticobiliary surgery. These findings should not be confused with hypervascular metastases. (orig.).

  3. Radiation dosage of various CT-methods in lung diagnostics

    International Nuclear Information System (INIS)

    Heinz-Peer, G.; Weninger, F.; Nowotny, R.; Herold, C.J.

    1996-01-01

    Introduction of the computed tomography index CTDI and the multiple scan average dose (MSAD) has led to standardization of the dose description in CT examinations. Despite the use of these dose parameters, many different dosages are reported in the literature for different CT methods. In addition, there is still a wide range of radiation dosimetry results reported for conventional CT, helical CT, and HRCT used in chest examinations. The variations in dosage are mainly due to difference in factors affecting the dose, i.e. beam geometry, beam quality, scanner geometry ('generation'), and operating parameters. In addition, CT dosimetry instrumentation and methodology make a contribution to dosages. Recent studies calculating differences in factors affecting dosage and CT dosimetry and using similar operating parameters, show similar results in CT dosimetry for conventional and helical CT. On the other hand, dosages for HRCT were greatly reduced. This was mainly caused by narrow beam collimation and increasing section spacing. (orig.) [de

  4. Role of CT scan in diagnosis of acute appendicitis

    International Nuclear Information System (INIS)

    Salem, O.A.; Khasawneh, M.

    2007-01-01

    To evaluate the diagnostic accuracy of the spiral-CT in patients with clinically suspected acute appendicitis. A total of 124 patients referred for CT scan with suspected appendicitis between January 2005 and October 2006 were assessed for the appendiceal size and the presence of signs of appendicitis. The findings were correlated with surgical histopathology. CT scan had a sensitivity of 95 percent and a specifity of 93 percent and an overall accuracy of 92 percent. The use of spiral CT in patients with equivocal clinical presentation suspected of having acute appendicitis can lead to significant improvement in the preoperative diagnosis. (author)

  5. SU-F-I-32: Organ Doses from Pediatric Head CT Scan

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H; Liu, Q; Qiu, J; Zhuo, W [Institute of Radiation Medicine Fudan University, Shanghai (China); Majer, M; Knezevic, Z; Miljanic, S [Radiation Chemistry and Dosimetry Laboratory, Ruder Boskovic Institute, Zagreb (Croatia); Hrsak, H [Clinical Hospital Centre Zagreb, Zagreb (Croatia)

    2016-06-15

    Purpose: To evaluate the organ doses of pediatric patients who undergoing head CT scan using Monte Carlo (MC) simulation and compare it with measurements in anthropomorphic child phantom.. Methods: A ten years old children voxel phantom was developed from CT images, the voxel size of the phantom was 2mm*2mm*2mm. Organ doses from head CT scan were simulated using MCNPX software, 180 detectors were placed in the voxel phantom to tally the doses of the represented tissues or organs. When performing the simulation, 120 kVp and 88 mA were selected as the scan parameters. The scan range covered from the top of the head to the end of the chain, this protocol was used at CT simulator for radiotherapy. To validate the simulated results, organ doses were measured with radiophotoluminescence (RPL) detectors, placed in the 28 organs of the 10 years old CIRS ATOM phantom. Results: The organ doses results matched well between MC simulation and phantom measurements. The eyes dose was showed to be as expected the highest organ dose: 28.11 mGy by simulation and 27.34 mGy by measurement respectively. Doses for organs not included in the scan volume were much lower than those included in the scan volume, thymus doses were observed more than 10 mGy due the CT protocol for radiotherapy covered more body part than routine head CT scan. Conclusion: As the eyes are superficial organs, they may receive the highest radiation dose during the CT scan. Considering the relatively high radio sensitivity, using shielding material or organ based tube current modulation technique should be encouraged to reduce the eye radiation risks. Scan range was one of the most important factors that affects the organ doses during the CT scan. Use as short as reasonably possible scan range should be helpful to reduce the patient radiation dose. This work was supported by the National Natural Science Foundation of China(11475047)

  6. CT-scanning in otolaryngology, 2

    International Nuclear Information System (INIS)

    Kusakari, Jun; Endo, Satomi; Hara, Akira

    1982-01-01

    Combined computerized tomography-sialography was performed in 28 patients with parotid tumors. Sialography was performed in the usual fashion. After confirming the presence of the contrast material within the parotid gland by X-ray, 4 to 5 scannings were done at the width of 10 mm below Repid's base line. With this procedure, the parotid gland was clearly demonstrated and the location of the tumor was shown as a shadow defect. Although the nature of the tumor, especially whether it was malignant or benign was difficult to predict, the CT-findings regarding the size and location of the tumor were completely coincident with the operative findings in all the cases. Accurate appraisal of the relation between the tumor and the facial nerve was possible in all but two cases. The preoperative information obtained from CT-scanning is extremely useful in the case of parotid tumor surgery. (author)

  7. Importance of repeated CT scan in Fournier gangrene treatment: clinical case

    International Nuclear Information System (INIS)

    Ignatenco, Sergiu

    2011-01-01

    A patient of 53 years presented fever, swelling and erythema in the perineal region. After computed tomography (CT) was diagnosed Fournier gangrene. After aggressive surgical debridement postoperative evolution was unfavorable. Repeated CT scan trace spread of infection to new areas that led to new surgical debridement on time. Use of CT scan in the postoperative period allows assessment of the effectiveness of surgical debridement and spread of infection. This article presents CT scan images and the most important periods of intraoperative surgical intervention. (authors)

  8. Serial CT scannings in herpes simplex encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, M.; Sawada, T.; Kuriyama, Y.; Kinugawa, H.; Yamaguchi, T. (National Cardivascular Center, Osaka (Japan))

    1981-10-01

    Two patients with serologically confirmed herpes simplex encephalitis were studied by serial CT scannings. Case 1, a 60-year-old woman, was admitted to National Cardiovascular Center because of headache, fever, and attacks of Jacksonian seizure. Case 2, a 54-year-old man, was admitted because of fever, consciousness disturbance and right hemiparesis. Pleocytosis (mainly lymphocytes) and elevation of protein content in cerebrospinal fluid were observed in both cases. Both patients presented ''das apallische Syndrom'' one month after admission. The diagnosis of herpes simplex encephalitis was confirmed by typical clinical courses and by greater than fourfold rises in serum antibody titer for herpes simplex virus as well as that in cerebrospinal fluid in case 1. Characteristic CT findings observed in these two cases were summarized as follows: Within a week after the onset, no obvious abnormalities could be detected on CT scans (Case 1). Two weeks after the onset, a large low-density area appeared in the left temporal lobe and in the contralateral insular cortex with midline shift toward the right side (Case 2). One month later, an ill-defined linear and ring-like high-density area (Case 1), or a well-defined high-density area (Case 2), that was enhanced after contrast administration, was observed in the large low-density area in the temporal lobe. These findings were considered as characteristic for hemorrhagic encephalitis. These high-density areas disappeared two months later, however, widespread and intensified low-density areas still remained. In both cases, the basal ganglia and thalamus were completely spared on CT scans. From these observations, it can be concluded that serial CT scannings are quite useful for diagnosis of herpes simplex encephalitis.

  9. Classication Methods for CT-Scanned Carcass Midsections

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke; Dahl, Anders Lindbjerg; Larsen, Rasmus

    2011-01-01

    Computed tomography (CT) has successfully been applied in medical environments for decades. In recent years CT has also made its entry to the industrial environments, including the slaughterhouses. In this paper we investigate classication methods for an online CT system, in order to assist...... in the segmentation of the outer fat layer in the mid- section of CT-scanned pig carcasses. Prior information about the carcass composition can potentially be applied for a fully automated solution, in order to optimize the slaughter line. The methods comprise Markov Random Field and contextual Bayesian classication...

  10. The helical three-dimensional CT in the diagnosis of torticollis with occipitocondylar hypoplasia

    International Nuclear Information System (INIS)

    Ilkko, E.; Tikkakoski, T.; Pyhtinen, J.

    1998-01-01

    Congenital anomalies of the atlanto-occipital and atlantoaxial joints are rare. Those most commonly reported are atlantoaxial instability, basilar impression, anomalies of the odontoid process, laxity of the transverse atlantal ligament and atlanto-occipital fusion. Occipital condylar hypoplasia is infrequent and difficult to recognise. We recently diagnosed it using helical 3D CT in association with torticollis in two patients. The first patient had a several year history of torticollis. The second patient had acute cervical lymphadenitis associated with post-operative torticollis. 3D CT distinctly revealed atlantoaxial subluxation with hypoplasia of the occipital condyles in both cases. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  11. Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

    Science.gov (United States)

    Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

    2009-10-01

    To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

  12. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Seco, Joao; Sørensen, Thomas Sangild

    2015-01-01

    Background. Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in...... development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. Material and methods. A CT calibration phantom and an abdomen cross section...... phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling...

  13. Protocol optimization in chest CT scans of child

    Energy Technology Data Exchange (ETDEWEB)

    Abrao L, L. T.; Amaral de O, F.; Prata M, A. [Biomedical Engineering Center, Centro Federal de Educacao Tecnologica de Minas Gerais, 30421-169, Belo Horizonte, Minas Gerais (Brazil); Bustos F, M., E-mail: luanaabrao@gmail.com [Universidad Federal de Minas Gerais, Department of Nuclear Engineering, Av. Pres. Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2017-10-15

    The dissemination of Computed Tomography (CT), a radiodiagnostic technique, has significant increase in the patient dose. In the last years, this technique has shown a high growth due to clinical cases of medical emergencies, neoplasm and pediatric traumas. Dose measurement is important to correlate with the deleterious effects of radiation on the organism and radiation future effects is related with stochastic risks due to tissue radiosensitivity, allied to the life expectancy of the child. In this work, a cylindrical phantom, representing an adult chest made of polymethylmethacrylate (PMMA), was used and a new born chest phantom with a shape oblong was developed based on the dimensions of a typical newborn. In a Ge CT scanner, Discovery model, with 64 channels, the central slice of the phantoms were irradiated successively in order to obtain dose measurements using an ionizing pencil camera. Based in the measurements, dose index was calculated (CTDI{sub vol}). The radiological service chest protocol using a voltage of 120 kV was used for scanning 10 cm of the central area of the adult and newborn phantom, in helical mode. An acquisition of images was performed using this radiological service chest protocol to compare with the protocol optimized. In the newborn phantom was also used protocols optimized using a voltage of 120 and 80 kV. The voltage of 80 kV has the lowest dose index for the pediatric object phantom. This work allowed the comparison between absorbed dose variations by the pediatric phantom changing the X-ray tube supply voltage. This dose variation has shown how important is specific protocols for children. (Author)

  14. Protocol optimization in chest CT scans of child

    International Nuclear Information System (INIS)

    Abrao L, L. T.; Amaral de O, F.; Prata M, A.; Bustos F, M.

    2017-10-01

    The dissemination of Computed Tomography (CT), a radiodiagnostic technique, has significant increase in the patient dose. In the last years, this technique has shown a high growth due to clinical cases of medical emergencies, neoplasm and pediatric traumas. Dose measurement is important to correlate with the deleterious effects of radiation on the organism and radiation future effects is related with stochastic risks due to tissue radiosensitivity, allied to the life expectancy of the child. In this work, a cylindrical phantom, representing an adult chest made of polymethylmethacrylate (PMMA), was used and a new born chest phantom with a shape oblong was developed based on the dimensions of a typical newborn. In a Ge CT scanner, Discovery model, with 64 channels, the central slice of the phantoms were irradiated successively in order to obtain dose measurements using an ionizing pencil camera. Based in the measurements, dose index was calculated (CTDI vol ). The radiological service chest protocol using a voltage of 120 kV was used for scanning 10 cm of the central area of the adult and newborn phantom, in helical mode. An acquisition of images was performed using this radiological service chest protocol to compare with the protocol optimized. In the newborn phantom was also used protocols optimized using a voltage of 120 and 80 kV. The voltage of 80 kV has the lowest dose index for the pediatric object phantom. This work allowed the comparison between absorbed dose variations by the pediatric phantom changing the X-ray tube supply voltage. This dose variation has shown how important is specific protocols for children. (Author)

  15. Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

    Science.gov (United States)

    Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

    2018-05-01

    We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some

  16. Spinal CT scan, 1. Cervical and thoracic spines

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Hiroshi (Aichi Medical Univ. (Japan))

    1982-01-01

    Methods of CT of the cervical and thoracic spines were explained, and normal CT pictures of them were described. Spinal CT was evaluated in comparison with other methods in various spinal diseases. Plain CT revealed stenosis due to spondylosis or ossification of posterior longitudinal ligament and hernia of intervertebral disc. CT took an important role in the diagnosis of spinal cord tumors with calcification and destruction of the bone. CT scan in combination with other methods was also useful for the diagnosis of spinal injuries, congenital anomalies and infections.

  17. CT-scanning of ancient Greenlandic Inuit temporal bones

    International Nuclear Information System (INIS)

    Homoe, P.; Videbaek, H.

    1992-01-01

    Additional morphological evidence of former infectious middle ear disease (IMED) was found by CT-scanning in 5 of 6 Greenlandic Inuit crania strongly suspected for former IMED due to earlier examination revealing either bilateral hypocellularity or asymmetry of the pneumatized area of the temporal bones. The CT-scans showed sclerosing and obliteration of the air cells and even destruction of the cellular septae, and a high degree of irregularity of the cells. Sclerosing of the surrounding bone tissue was also found. The findings in one cranium were dubious and could both be regarded as a congenital malformation or an infection in infanthood. CT-scan confirms and even adds to the results of conventional X-ray of temporal bones making hypotheses of paleopathology more reliable. The findings also support the environmental theory of pneumatization of the air cell system in the temporal bones. (13 refs., 10 figs.)

  18. CT-scanning of ancient Greenlandic Inuit temporal bones

    Energy Technology Data Exchange (ETDEWEB)

    Homoe, P [Copenhagen Univ. (Denmark). Lab. of Biological Anthropology and Dept. of Otolaryngology, Head and Neck Surgery; Lynnerup, N [Copenhagen Univ., Lab. of Biological Anthropology and Univ. Inst. of Ferensic Medicine, Copenhagen (Denmark); Videbaek, H [Hvidovre Univ. Hospital, Copenhagen (Denmark). Dept. of Radiology

    1992-01-01

    Additional morphological evidence of former infectious middle ear disease (IMED) was found by CT-scanning in 5 of 6 Greenlandic Inuit crania strongly suspected for former IMED due to earlier examination revealing either bilateral hypocellularity or asymmetry of the pneumatized area of the temporal bones. The CT-scans showed sclerosing and obliteration of the air cells and even destruction of the cellular septae, and a high degree of irregularity of the cells. Sclerosing of the surrounding bone tissue was also found. The findings in one cranium were dubious and could both be regarded as a congenital malformation or an infection in infanthood. CT-scan confirms and even adds to the results of conventional X-ray of temporal bones making hypotheses of paleopathology more reliable. The findings also support the environmental theory of pneumatization of the air cell system in the temporal bones. (13 refs., 10 figs.).

  19. Respiratory-Gated Helical Computed Tomography of Lung: Reproducibility of Small Volumes in an Ex Vivo Model

    International Nuclear Information System (INIS)

    Biederer, Juergen; Dinkel, Julien; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata M.Sc.; Thierfelder, Carsten; Mende, Ulrich; Debus, Juergen; Heller, Martin; Kauczor, Hans-Ulrich

    2007-01-01

    Purpose: Motion-adapted radiotherapy with gated irradiation or tracking of tumor positions requires dedicated imaging techniques such as four-dimensional (4D) helical computed tomography (CT) for patient selection and treatment planning. The objective was to evaluate the reproducibility of spatial information for small objects on respiratory-gated 4D helical CT using computer-assisted volumetry of lung nodules in a ventilated ex vivo system. Methods and Materials: Five porcine lungs were inflated inside a chest phantom and prepared with 55 artificial nodules (mean diameter, 8.4 mm ± 1.8). The lungs were respirated by a flexible diaphragm and scanned with 40-row detector CT (collimation, 24 x 1.2 mm; pitch, 0.1; rotation time, 1 s; slice thickness, 1.5 mm; increment, 0.8 mm). The 4D-CT scans acquired during respiration (eight per minute) and reconstructed at 0-100% inspiration and equivalent static scans were scored for motion-related artifacts (0 or absent to 3 or relevant). The reproducibility of nodule volumetry (three readers) was assessed using the variation coefficient (VC). Results: The mean volumes from the static and dynamic inspiratory scans were equal (364.9 and 360.8 mm 3 , respectively, p = 0.24). The static and dynamic end-expiratory volumes were slightly greater (371.9 and 369.7 mm 3 , respectively, p = 0.019). The VC for volumetry (static) was 3.1%, with no significant difference between 20 apical and 20 caudal nodules (2.6% and 3.5%, p = 0.25). In dynamic scans, the VC was greater (3.9%, p = 0.004; apical and caudal, 2.6% and 4.9%; p = 0.004), with a significant difference between static and dynamic in the 20 caudal nodules (3.5% and 4.9%, p = 0.015). This was consistent with greater motion-related artifacts and image noise at the diaphragm (p <0.05). The VC for interobserver variability was 0.6%. Conclusion: Residual motion-related artifacts had only minimal influence on volumetry of small solid lesions. This indicates a high reproducibility of

  20. The value of contrast-enhanced CT scan in prediction of development of contusional hemorrhage

    International Nuclear Information System (INIS)

    Yokoyama, Kazuhiro; Kyoi, Kikuo; Sakaki, Toshisuke; Kinugawa, Kazuhiko; Morimoto, Tetsuya

    1983-01-01

    It is often experienced that even if there are no significant findings on the initial plain CT scan in the patient with cerebral contusion, the patient has thereafter a serious clinical course and requires emergency operation for so-called contusional hemorrhage. In order to predict of the development of contusional hemorrhage we performed contrast-enhanced CT scan at the time of patient's arrival within 12 hours after injury, if there was cerebral contusion on the initial plain CT scan, and repeated plain CT scan 24 hours after the contrast-enhanced CT scan. If enhancement was demonstrated on the contrastenhanced CT scan, we predicted the development of contusional hemorrhage and if not demonstrated, we predicted no more development of contusional hemorrhage and then we studied the correlation between the prediction and the plain CT 24 hours after the contrast-enhanced CT scan. The results were as follows: 1) The prediction was correct in 13 cases out of 16 cases in which the development of contusional hemorrhage was observed. In 18 cases where no development of contusional hemorrhage was observed, the prediction was correct without exception. 2) Most of the cases in which enhancement was demonstrated were ones examined not before 3 hours after injury. 3) The extent of enhancement shown on contrastenhanced CT scan was well consistent with that of contusional hemorrhage on the plain CT scan 24 hours after the contrast-enhanced CT scan. From these results, the contrast-enhanced CT scan in acute stage of head injury was considered to by very useful in prediction of the development of contusional hemorrhage. (author)

  1. Motion tolerant iterative reconstruction algorithm for cone-beam helical CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hisashi; Goto, Taiga; Hirokawa, Koichi; Miyazaki, Osamu [Hitachi Medical Corporation, Chiba-ken (Japan). CT System Div.

    2011-07-01

    We have developed a new advanced iterative reconstruction algorithm for cone-beam helical CT. The features of this algorithm are: (a) it uses separable paraboloidal surrogate (SPS) technique as a foundation for reconstruction to reduce noise and cone-beam artifact, (b) it uses a view weight in the back-projection process to reduce motion artifact. To confirm the improvement of our proposed algorithm over other existing algorithm, such as Feldkamp-Davis-Kress (FDK) or SPS algorithm, we compared the motion artifact reduction, image noise reduction (standard deviation of CT number), and cone-beam artifact reduction on simulated and clinical data set. Our results demonstrate that the proposed algorithm dramatically reduces motion artifacts compared with the SPS algorithm, and decreases image noise compared with the FDK algorithm. In addition, the proposed algorithm potentially improves time resolution of iterative reconstruction. (orig.)

  2. Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?

    Energy Technology Data Exchange (ETDEWEB)

    Nattenmüller, Johanna, E-mail: johanna.nattenmueller@med.uni-heidelberg.de; Filsinger, Matthias, E-mail: Matthias_filsinger@web.de; Bryant, Mark, E-mail: mark.bryant@med.uni-heidelberg.de; Stiller, Wolfram, E-mail: Wolfram.Stiller@med.uni-heidelberg.de; Radeleff, Boris, E-mail: boris.radeleff@med.uni-heidelberg.de; Grenacher, Lars, E-mail: lars.grenacher@med.uni-heidelberg.de; Kauczor, Hans-Ullrich, E-mail: hu.kauczor@med.uni-heidelberg.de; Hosch, Waldemar, E-mail: waldemar.hosch@urz.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2013-06-19

    PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only.

  3. Complications in CT-guided Procedures: Do We Really Need Postinterventional CT Control Scans?

    International Nuclear Information System (INIS)

    Nattenmüller, Johanna; Filsinger, Matthias; Bryant, Mark; Stiller, Wolfram; Radeleff, Boris; Grenacher, Lars; Kauczor, Hans-Ullrich; Hosch, Waldemar

    2014-01-01

    PurposeThe aim of this study is twofold: to determine the complication rate in computed tomography (CT)-guided biopsies and drainages, and to evaluate the value of postinterventional CT control scans.MethodsRetrospective analysis of 1,067 CT-guided diagnostic biopsies (n = 476) and therapeutic drainages (n = 591) in thoracic (n = 37), abdominal (n = 866), and musculoskeletal (ms) (n = 164) locations. Severity of any complication was categorized as minor or major. To assess the need for postinterventional CT control scans, it was determined whether complications were detected clinically, on peri-procedural scans or on postinterventional scans only.ResultsThe complication rate was 2.5 % in all procedures (n = 27), 4.4 % in diagnostic punctures, and 1.0 % in drainages; 13.5 % in thoracic, 2.0 % in abdominal, and 3.0 % in musculoskeletal procedures. There was only 1 major complication (0.1 %). Pneumothorax (n = 14) was most frequent, followed by bleeding (n = 9), paresthesia (n = 2), material damage (n = 1), and bone fissure (n = 1). Postinterventional control acquisitions were performed in 65.7 % (701 of 1,067). Six complications were solely detectable in postinterventional control acquisitions (3 retroperitoneal bleeds, 3 pneumothoraces); all other complications were clinically detectable (n = 4) and/or visible in peri-interventional controls (n = 21).ConclusionComplications in CT-guided interventions are rare. Of these, thoracic interventions had the highest rate, while pneumothoraces and bleeding were most frequent. Most complications can be detected clinically or peri-interventionally. To reduce the radiation dose, postinterventional CT controls should not be performed routinely and should be restricted to complicated or retroperitoneal interventions only

  4. Serial CT scans and Menkes' kinky hair disease

    International Nuclear Information System (INIS)

    Nakada, Eizo; Kameyama, Junji; Yoshimitsu, Hajime; Mori, Mikio; Tanaka, Mutsuo; Yoshimitsu, Kazunori.

    1988-01-01

    Menkes' kinky hair disease is a sex-linked recessive disorder of copper metabolism, characterized by progressive psychomotor deterioration, seizures, and peculiar hair structure. We examined serial CT scans of patients with this disease. A 2,210-g male infant was delivered after an uneventful gestation of 36 weeks. His one-minute Apgar score was 9. His uncle had died at 1 year of age. His first cousin was also diagnosed as having Menkes' kinky hair disease when our patient was 2 years old. Shortly after birth he had mild respiratory distress. At 5 days of age, he developed setting-sun signs. The first CT scan, at 10 days of age, revealed mild posterior fossa hemorrhages. At 3 months of age, myoclonic seizures began, and the CT scan revealed subdural effusion and mild brain atrophy. The seizures were controllable by using phenobarbital, valproic acid, and nitrazepam. He did not follow light or a fixate, but the fundi were normal. He was diffusely hypotonic. At 9 months of age, the seizures became uncontrollable. The CT scans at 15 and 31 months of age showed subdural hemorrhage and/or brain atrophy. At 15 months of age, the serum copper level was 42 μ g/dl, while the serum ceruloplasmin level was 3.2 mg/dl. He exhibited severe developmental failure. At 4 years of age, he died. (author)

  5. CT scan of pituitary adenomas

    International Nuclear Information System (INIS)

    Sakoda, K.; Mukada, K.; Yonezawa, M.; Matsumura, S.; Yoshimoto, H.; Mori, S.; Uozumi, T.

    1981-01-01

    CT scan is an extremely useful, almost harmless means of diagnosing pituitary adenomas. Growth hormone (GH)-secreting adenomas tend to have higher absorption coefficent in plain CT than the nonfunctioning and prolactin (PRL)-secreting adenomas. The absorption coefficent on contrast-enhanced CT does not identify the specific type of adenoma. Ring-like enhancement was observed in five nonfunctioning and four PRL-secreting adenomas with suprasellar extension, while cystic components were observed in four nonfunctioning and four PRL-secreting adenomas. In three of ten cases of PRL-secreting microadenomas, the site corresponding to the adenoma was not enhanced, whereas the normal pituitary was. A correlation exists between the size of PRL-secreting adenoma and the serum PRL level, but not between the size of GH-secreting adenomas and the serum GH level. (orig.)

  6. Scan Quality and Entrance Skin Dose in Thoracic CT: A Comparison between Bismuth Breast Shield and Posteriorly Centered Partial CT Scans

    International Nuclear Information System (INIS)

    Tappouni, Rafel; Mathers, Bradley

    2012-01-01

    Objectives. To compare the effectiveness of the bismuth breast shield and partial CT scan in reducing entrance skin dose and to evaluate the effect of the breast shield on image quality (IQ). Methods. Nanodots were placed on an adult anthropomorphic phantom. Standard chest CT, CT with shield, and partial CT were performed. Nanodot readings and effective doses were recorded. 50 patients with chest CTs obtained both with and without breast shields were reviewed. IQ was evaluated by two radiologists and by measuring Hounsfield units (HUs) and standard deviation (SD) of HU in anterior subcutaneous region. Results. Breast shield and the partial CT scans reduced radiation to the anterior chest by 38% and 16%, respectively. Partial CT increased dose to the posterior chest by 37% and effective dose by 8%. Change in IQ in shield CT was observed in the anterior chest wall. Significant change in IQ was observed in 5/50 cases. The shield caused an increase of 20 HU (P = 0.021) and a 1.86 reduction in SD of HU (P = 0.027) in the anterior compared to posterior subcutaneous regions. Summary. Bismuth breast shield is more effective than the partial CT in reducing entrance skin dose while maintaining image quality

  7. Adult head CT scans: the uncertainties of effective dose estimates

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2008-01-01

    Full Text: CT scanning is a high dose imaging modality. Effective dose estimates from CT scans can provide important information to patients and medical professionals. For example, medical practitioners can use the dose to estimate the risk to the patient, and judge whether this risk is outweighed by the benefits of the CT examination, while radiographers can gauge the effect of different scanning protocols on the patient effective dose, and take this into consideration when establishing routine scan settings. Dose estimates also form an important part of epidemiological studies examining the health effects of medical radiation exposures on the wider population. Medical physicists have been devoting significant effort towards estimating patient radiation doses from diagnostic CT scans for some years. The question arises: How accurate are these effective dose estimates? The need for a greater understanding and improvement of the uncertainties in CT dose estimates is now gaining recognition as an important issue (BEIR VII 2006). This study is an attempt to analyse and quantify the uncertainty components relating to effective dose estimates from adult head CT examinations that are calculated with four commonly used methods. The dose estimation methods analysed are the Nagel method, the ImpaCT method, the Wellhoefer method and the Dose-Length Product (DLP) method. The analysis of the uncertainties was performed in accordance with the International Standards Organisation's Guide to the Expression of Uncertainty in Measurement as discussed in Gregory et al (Australas. Phys. Eng. Sci. Med., 28: 131-139, 2005). The uncertainty components vary, depending on the method used to derive the effective dose estimate. Uncertainty components in this study include the statistical and other errors from Monte Carlo simulations, uncertainties in the CT settings and positions of patients in the CT gantry, calibration errors from pencil ionization chambers, the variations in the organ

  8. Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

    International Nuclear Information System (INIS)

    Neuwelt, E.A.; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

    1983-01-01

    Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented

  9. Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Tilo [Cantonal Hospital Baden, Department of Radiology, Baden (Switzerland); University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Colas, Lucie; Santangelo, Teresa; Faivre, Jean Baptiste; Remy, Jacques; Remy-Jardin, Martine [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Roser, Hans W.; Bremerich, Jens [University of Basel Hospital, Clinic of Radiology and Nuclear Medicine, Medical Physics, Basel (Switzerland)

    2015-03-01

    The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort. A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks. Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates. Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates. (orig.)

  10. Automated image quality assessment for chest CT scans.

    Science.gov (United States)

    Reeves, Anthony P; Xie, Yiting; Liu, Shuang

    2018-02-01

    Medical image quality needs to be maintained at standards sufficient for effective clinical reading. Automated computer analytic methods may be applied to medical images for quality assessment. For chest CT scans in a lung cancer screening context, an automated quality assessment method is presented that characterizes image noise and image intensity calibration. This is achieved by image measurements in three automatically segmented homogeneous regions of the scan: external air, trachea lumen air, and descending aorta blood. Profiles of CT scanner behavior are also computed. The method has been evaluated on both phantom and real low-dose chest CT scans and results show that repeatable noise and calibration measures may be realized by automated computer algorithms. Noise and calibration profiles show relevant differences between different scanners and protocols. Automated image quality assessment may be useful for quality control for lung cancer screening and may enable performance improvements to automated computer analysis methods. © 2017 American Association of Physicists in Medicine.

  11. Topographic diagnosis of parathyroid tumor by CT scan

    International Nuclear Information System (INIS)

    Fukunaga, Masao; Harioka, Toshio; Morita, Rikuji

    1981-01-01

    In order to detect the hyperfunctioning parathyroid gland(s), CT scan over the neck was performed in patients with parathyroid disorders, including 10 primary hyperparathyroidism (6 bone type, 3 stone type and 1 chemical type), 8 chronic renal failure on hemodialysis with renal osteodystrophy and 2 multiple endocrine adenomatosis (MEA) type I. We used a whole-body scanner (CT/T, GE). The slice thickness was 5 mm. All patients were scanned from the sternal notch upward to the larynx, and were enhanced by the administration of 30% DIP Conray for 15 min. The results of the topographic diagnosis were compared with the surgical findings. Precise preoperative localization was accomplished in 9/10 adenomas in primary hyperparathyroidism, 27/32 hyperplasias in secondary hyperparathyroidism, and 2/4 hyperplasias in MEA type I. The smallest lesion weighed 0.2 g. It was shown that CT scan over the neck was a noninvasive and simple method to define the localization of hyperfunctionig parathyroid gland(s). (author)

  12. Dual purpose QA tool developed for teletherapy unit and CT scan in SNDH

    International Nuclear Information System (INIS)

    Shilvant, D.V.; Tamane, C.J.; Pangam, S.B.; Raees, M.D.; Aynoor, S.K.; Pol, P.S.; Verghese, Aju; Ghorpade, C.J.

    2007-01-01

    To make a simple device used in Teletherapy unit and CT scan for depth data measurement. The accurate depth data is essential and very important factor for precise treatment in SAD isocentric setup calculation. In CT scan based treatment planning, the calculation obtained is from the depth given by the CT scan. The success of treatment depends on the same parameters in treatment unit matched with diagnostic CT scan data. To check the depth parameters in both CT scan and Teletherapy unit we have developed a single QA tool in our hospital. As this tool is precise, handy and easily accessible the results obtained from it assures the quality of Teletherapy unit as well as CT scan depth data. This small device resulted data helps a lot in calculations of complicated SAD setup in Telecobalt and also useful in recent new treatment modalities such as IMRT, micro MLC, etc

  13. Contrast bolus technique with rapid CT scanning

    International Nuclear Information System (INIS)

    Arnold, H.; Kuehne, D.; Rohr, W.; Heller, M.

    1981-01-01

    Twenty-three patients complying with the clinical criteria for brain death were studied by contrast-enhanced CT. In all but one, the great intracranial vessels escaped visualization; accordingly, angiography demonstrated cerebral circulatory arrest. In the remaining case, faint enhancement of the circle of Willis corresponded to angiographic demonstration of the proximal segments of cerebral arteris. Neither in normal brain nor in dead brain did slow CT scanning disclose any postcontrast increase in parenchymal attenuation. An improved technique is proposed to demonstrate the transit of the contrast bolus by rapid CT with image splitting. If cerebral blood flow is preserved, the grey and white matter will enhance significantly following administration of contrast medium. Vice versa, the absence of enhancement confirms brain death, even in instances in which the great cerebral vessels are obscured by hemorrhage or other extensive lesions. Two additional cases of brain death were evaluated by rapid CT scanning. As to brain death, the technique obviates the need for angiography or radionuclide angiography, usually applied in prospective organ donors, because its informative content is superior to that of either method. The CT technique described affords a reliable and safe diagnosis of brain death, and can be interpreted easily. (orig.)

  14. Three dimensional CT of stapes. Stapedial imagings in dry temporal bone and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Edamatsu, Hideo; Kubota, Osamu; Yamashita, Koichi [Kanazawa Medical Univ., Ishikawa (Japan)

    1995-03-01

    This study was performed to evaluate the usefulness and limitations of three dimensional (3-D) imagings of stapes in the middle ear by high speed helical CT. One dissected human temporal bone, ten normal and diseased ears were scanned with a slice of 1.0 mm and reconstructed in a thickness of 0.2-0.5 mm. Every specimen of 3-D can be observed in any plane and from any direction. Ossicular imagings of the temporal bone in 3-D were reconstructed as if the malleus, incus and stapes were observed under microscope. The whole structure of stapes was impossible to be represented by two dimensional CT heretofore in use, but 3-D in our study showed the head, crus and foot plate of the stapes in detail. Stapedial imagings of 3-D CT in normal ears showed the same findings as those recorded in temporal bone. Preoperative diagnostic findings of ossicles in the affected ears were very useful. Especially in ossicular anomalies, 3-D CT was positive in diagnosis and its accuracies were confirmed with operative observation. For the postoperative evaluation concerning the ossicular reconstruction, i.e. TORP and PORP, 3-D CT was also important method. It could present an anatomical relation between those prosthesis and the oval window. High speed helical CT can scan an object more quickly and clearly than formerly used CT, and its biological damage for human is less than that of the others. 3-D CT can be more clearly reconstructed with helical CT than former CT. (author).

  15. Demonstration of the right inferior phrenic artery by using multislice helical CT

    International Nuclear Information System (INIS)

    Zhao Shaohong; Liu Xin; Cai Zulong; Zhao Hong; Yang Li

    2006-01-01

    Objective: To demonstrate the origin of the right inferior phrenic artery (RIPA) in normal and hepatocellular carcinoma (HCC) patients and provide valuable anatomical information for angiographers before and after transcatheter arterial chemoembolization (TACE). Methods: Four hundred and forty consecutive patients including 133 HCC cases who had biphase abdominal CT were assessed in this study. The routine abdominal enhanced CT scan (GE, LightSpeed16) was performed with 120 kV, 200-240 mAs, 10 mm collimation, 1.375 pitch, and 10 mm reconstruction interval at 22-25 seconds for arterial phase triggered by timing bolus, 60 seconds for portal venous phase after injection of 100 ml contrast material (300 mg I/ml) at a rate of 3.5 ml/s. Multiplanar reconstruction (MPR) and maximum intensity projection (MIP) images were generated using 1.25 mm images reconstructed with 1 mm interval in arterial phase and reviewed by two radiologists. An enhanced artery medial-posterior to the IVC, originated from aorta or its branches to the diaphragmatic dome was interpreted as the RIPA. Results: The RIPA was showed in all 440 patients (100%). Among 218 (49.5%) RIPAs originated from the aorta, 140 were from the fight side of the aorta, 22 from the left side of the aorta, 56 from the anterior wall of the aorta, 36 RIPAs had the same origin with the left inferior phrenic artery. Among 138 (31.4%) RIPAs from the celiac artery, 10 RIPAs had the same origin with the left gastric artery, and 33 RIPAs had the same origin with the left inferior phrenic artery. 78 (17.7%) were from the fight renal artery, 6 (1.4%) were from the left gastric artery (the left gastric artery from aorta). The dilatation of the RIPA was demonstrated in 16 of 133 hepatocellular carcinoma patients. Conclusion: Multislice helical CT could demonstrate the origin of the RIPA in arterial phase and provide useful anatomical information for angiographer before and after TACE. (authors)

  16. Impact of the planning CT scan time on the reflection of the lung tumor motion

    International Nuclear Information System (INIS)

    Kim, Su San; Choi, Eun Kyung; Yi, Byong Yong; Ha, Sung Whan

    2004-01-01

    To evaluate the reflection of tumor motion according to the planning CT scan time. A model of N-shape, which moved along the longitudinal axis during the ventilation caused by a mechanical ventilator, was produced. The model was scanned by planning CT, while setting the relative CT scan time (T; CT scan time/ventilatory period) to 0.33, 0.50, 0.67, 0.75, 1.00, 1.33 T, and 1.53 T. In addition, three patients with non-small cell lung cancer who received stereotactic radiosurgery in the Department of Radiation Oncology, Asan Medical Center from 03/19/2002 to 05/21/2002 were scanned. Slow (IQ Premier, Picker, scan time 2.0 seconds per slice) and fast CT scans (Light Speed, GE Medical System, with a scan time of 0.8 second per slice) were performed for each patient. The magnitude of reflected movement of the N-shaped model was evaluated by measuring the transverse length, which reflected the movement of the declined bar of the model at each slice. For patients' scans, all CT data sets were registered using a stereotactic body frame scale with the gross tumor volumes delineated in one CT image set. The volume and three-dimensional diameter of the gross tumor volume were measured and analyzed between the slow and fast CT scans. The reflection degree of longitudinal movement of the model increased in proportion to the relative CT scan times below 1.00 T, but remained constant above 1.00 T. Assuming the mean value of scanned transverse lengths with CT scan time 1.00 T to be 100%, CT scans with scan times of 0.33, 0.50, 0.67, and 0.75 T missed the tumor motion by 30, 27, 20, and 7.0% respectively. Slow (scan time 2.0 sec) and Fast (scan time 0.8 sec) CT scans of three patients with longitudinal movement of 3, 5, and 10 mm measured by fluoroscopy revealed the increases in the diameter along the longitudinal axis increased by 6.3, 17, and 23% in the slow CT scans. As the relative CT scan time increased, the reflection of the respiratory tumor movement on planning CT also

  17. A simulation study on proton computed tomography (CT) stopping power accuracy using dual energy CT scans as benchmark.

    Science.gov (United States)

    Hansen, David C; Seco, Joao; Sørensen, Thomas Sangild; Petersen, Jørgen Breede Baltzer; Wildberger, Joachim E; Verhaegen, Frank; Landry, Guillaume

    2015-01-01

    Accurate stopping power estimation is crucial for treatment planning in proton therapy, and the uncertainties in stopping power are currently the largest contributor to the employed dose margins. Dual energy x-ray computed tomography (CT) (clinically available) and proton CT (in development) have both been proposed as methods for obtaining patient stopping power maps. The purpose of this work was to assess the accuracy of proton CT using dual energy CT scans of phantoms to establish reference accuracy levels. A CT calibration phantom and an abdomen cross section phantom containing inserts were scanned with dual energy and single energy CT with a state-of-the-art dual energy CT scanner. Proton CT scans were simulated using Monte Carlo methods. The simulations followed the setup used in current prototype proton CT scanners and included realistic modeling of detectors and the corresponding noise characteristics. Stopping power maps were calculated for all three scans, and compared with the ground truth stopping power from the phantoms. Proton CT gave slightly better stopping power estimates than the dual energy CT method, with root mean square errors of 0.2% and 0.5% (for each phantom) compared to 0.5% and 0.9%. Single energy CT root mean square errors were 2.7% and 1.6%. Maximal errors for proton, dual energy and single energy CT were 0.51%, 1.7% and 7.4%, respectively. Better stopping power estimates could significantly reduce the range errors in proton therapy, but requires a large improvement in current methods which may be achievable with proton CT.

  18. Comparison of CT scanning and radionuclide imaging in liver disease

    International Nuclear Information System (INIS)

    Friedman, M.L.; Esposito, F.S.

    1980-01-01

    Early experience with body CT suggested its usefulness in many diagnostic problems; jaundice, renal and pancreatic masses, and in the evaluation of relatively inaccessible parts of the body, such as the retroperitineum, mediastinum, and pelvis. Investigation of hepatic disease by CT was not unexpectedly compared to radionuclide liver scanning, the major preexisting modality for imaging the liver. In the evaluation of the jaundiced patient, CT rapidly assumed a major role, providing more specific information about the liver than the RN liver scan, as well as demonstrating adjacent organs. CT differentiate obstructive from non-obstructive jaundice. With respect to mass lesions of the liver, the RN liver scan is more sensitive than CT but less specific. The abnormalities on an isotope image of the liver consist of normal variants in configuration, extrinsic compression by adjacent structures, cysts, hemangiomata, abscesses, and neoplasms. These suspected lesions may then be better delineated by the CT image, and a more precise diagnosis made. The physiologic information provided by the RN liver scan is an added facet which is helpful in the patient with diffuse hepatic disease. The CT image will be normal in many of these patients, however, hemochromatosis and fatty infiltration lend themselves especially to density evaluation by CT. The evaluation of lymphoma is more thorough with CT. Structures other than the liver, such as lymph nodes, are visualized. Gallium, however, provides additional isotopic information in patients with lymphoma, and in addition, is known to be useful in the investigation of a febrile patient with an abscess. Newer isotopic agents expand hepatic imaging in other directions, visualizing the biliary tree and evaluating the jaundiced patient

  19. Vascular anatomy of the liver and porta hepatis with dynamic CT scan

    International Nuclear Information System (INIS)

    Hiramatsu, Yoshihiro; Wada, Mitsuyoshi; Nakajima, Teiichi; Tonooka, Reiko; Matsumoto, Kunihiko

    1983-01-01

    Vascular anatomy of the liver and porta heaptis demonstrated by dynamic CT scan was studied Identification of the individual vessels was sometimes difficult due to slight differencies in respiratory depths among the scans. Limitation in the number of slices also made the evalution of the vascular anatomy difficult. Angiography was therefore utilized for comparison in identifying the vessels. Dynamic CT scan was proved to be usefull in demonstrating the anteroposterior relationship of the vessels and surrounding structures, which is difficult with convetional angiography without multiple projections. Three dimensional understanding of the vessels was then possible with dynamic CT scan and angiography. When combined with recently advancing digital subtraction angiography, dynamic CT scan might reduce the necessity for conventional angiography with Seldinger's technique. (author)

  20. CT scans in encephalitis

    International Nuclear Information System (INIS)

    Imanishi, Masami; Morimoto, Tetsuya; Iida, Noriyuki; Hisanaga, Manabu; Kinugawa, Kazuhiko

    1980-01-01

    Generally, CT scans reveal a decrease in the volume of the ventricular system, sylvian fissures and cortical sulci in the acute stage of encephalitis, and softening of the cerebral lobes with dilatation of the lateral ventricles and subarachnoidian dilated spaces in the chronic stage. We encountered three cases of encephalitis: mumps (case 1), herpes simplex (case 2), and syphilis (case 3). In case 1, brain edema was seen in the acute stage and brain atrophy in the chronic stage. In case 2, necrosis of the temporal pole, which is pathognomonic in herpes simplex encephalitis, was recognized. And in case 3, multiple lesions whose CT appearance was enhanced by contrast materials were found scattered over the whole brain. These lesions were diagnosed as inflammatory granuloma by histological examination. (author)

  1. Intravenous digital subtraction angiography and helical computed tomography in evaluation of living renal donors

    International Nuclear Information System (INIS)

    Watarai, Yoshihiko; Usuki, Tomoaki; Takeuchi, Ichiro; Nonomura, Katsuya; Koyanagi, Tomohiko; Kubo, Kozo; Hirano, Tetsuo; Togashi, Masaki; Ohashi, Nobuo

    2001-01-01

    The present study was carried out to evaluate the accuracy of helical computed tomography (CT) and intravenous digital subtraction angiography (IV-DSA) on anatomical assessment of renal vasculature for living renal donors. Forty-two healthy potential renal donors were prospectively evaluated and 35 subsequently underwent donor nephrectomy after helical CT and IV-DSA evaluation. The vascular and non-vascular findings were compared between the findings on helical CT, IV-DSA and surgery. Ten prehilar branches and five accessory renal arteries were found at nephrectomy. Overall, operative findings agreed with the findings by IV-DSA in 89% and by helical CT in 83%. In delineating accessory arteries, IV-DSA had a sensitivity of 60% and specificity of 97%, whereas helical CT had a sensitivity of 40% and specificity of 100%. In delineating prehilar branches, IV-DSA had a sensitivity of 90% and specificity of 100%, whereas helical CT had a sensitivity of 70% and specificity of 100%. Accessory arteries and prehilar branches that were not detected by helical CT or IV-DSA, were less than 2 mm in diameter and did not require vascular reconstruction. Renal veins were delineated in 63% by IV-DSA, whereas they were clearly imaged by helical CT in all cases, including a case with a circumaortic renal vein. Non-vascular findings were obtained in 64% by helical CT, including two renal tumors. None of these findings were obtained by IV-DSA. Helical CT and IV-DSA provide comparably sufficient information on renal artery vasculature. However, helical CT provides significantly more information on venous and non-vascular findings as a single-imaging modality. (author)

  2. Relationship between Hounsfield Unit in CT Scan and Gray Scale in CBCT

    Directory of Open Access Journals (Sweden)

    Tahmineh Razi

    2014-06-01

    Full Text Available Background and aims. Cone-beam computed tomography (CBCT is an imaging system which has many advantages over computed tomography (CT. In CT scan, Hounsfield Unit (HU is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value. The aim of the present study was to investigate the relationship between gray scale in CBCT and Hounsfield Unit (HU in CT scan. Materials and methods. In this descriptive study, the head of a sheep was scanned with 3 CBCT and one medical CT scanner. Gray scales and HUs were detected on images. Reconstructed data were analyzed to investigate relationship between CBCT gray scales and HUs. Results. A strong correlation between gray scales of CBCT and HUs of CT scan was determined. Conclusion. Considering the fact that gray scale in CBCT is the criteria in measurement of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

  3. The significance of multi-slice helical CT multiplanar reconstruction in the diagnoses of laryngeal carcinoma

    International Nuclear Information System (INIS)

    Li Lin; Luo Dehong; Zhou Chunwu; Zhao Xinming; Jiang Liming; Huang Yao; Jiang Lingxia; Li Jing; Wu Ning

    2006-01-01

    Objective: To evaluate the significance of multi-slice helical CT with multiplanar reconstruction in laryngeal carcinoma. Methods: Thirty-five patients with laryngeal carcinoma were studied by helical CT, MPR were subsequently done. The lesion extent of the axial image findings, MPR findings and the combined image findings were compared with the pathological results respectively. The data were statistically analyzed. Results: In the evaluation of the anterior commissure, the axial image findings, MPR findings and the combined image findings were 82.9%, 68.6% and 91.4% in accuracy respectively, the results were statistically different (P 0.05). The combined images were superior to the axial images and the MPR images in sensitivity, specificity and accuracy of the lesion extent. Conclusion: The axial images could show the shape, size, extension of the tumor and the lymphadenopathy, MPR images displayed the shape, size and extension roundly and directly, they were the supplement for the axial images. Axial images combined with MPR could improve the accuracy in the diagnoses of laryngeal carcinoma. (authors)

  4. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    International Nuclear Information System (INIS)

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A.; Chen, Allen M.

    2010-01-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive

  5. The prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint in patients with mandibular prognathism without internal derangement. MR and helical CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Takafumi; Ito, Jusuke; Tanaka, Rei; Koyama, Jun-ichi; Kobayashi, Fukiko [Niigata Univ. (Japan). Graduate School of Medical and Dental Sciences

    2002-06-01

    The aim of this study was to assess the prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint without internal derangement. Sixty joints of 30 consecutive patients with mandibular prognathism were evaluated with both MR imaging and helical CT. On MPR images obtained with helical CT, erosive osseous changes of the articular eminence were observed in 18 joints (30%) of 13 patients. None of the joints studied demonstrated an osseous change in the mandibular condyle. MR imaging failed to detect erosive osseous changes of the articular eminence in all of the joints studied. In conclusion, MPR images obtained with helical CT were of value to detect erosive osseous changes of the articular eminence. (author)

  6. The prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint in patients with mandibular prognathism without internal derangement. MR and helical CT findings

    International Nuclear Information System (INIS)

    Hayashi, Takafumi; Ito, Jusuke; Tanaka, Rei; Koyama, Jun-ichi; Kobayashi, Fukiko

    2002-01-01

    The aim of this study was to assess the prevalence of erosive osseous changes of the articular eminence in the temporomandibular joint without internal derangement. Sixty joints of 30 consecutive patients with mandibular prognathism were evaluated with both MR imaging and helical CT. On MPR images obtained with helical CT, erosive osseous changes of the articular eminence were observed in 18 joints (30%) of 13 patients. None of the joints studied demonstrated an osseous change in the mandibular condyle. MR imaging failed to detect erosive osseous changes of the articular eminence in all of the joints studied. In conclusion, MPR images obtained with helical CT were of value to detect erosive osseous changes of the articular eminence. (author)

  7. Reducing radiation dose in liver enhanced CT scan by setting mAs according to plain scan noise

    International Nuclear Information System (INIS)

    Yang Shangwen; He Jian; Yang Xianfeng; Zhou Kefeng; Xin Xiaoyan; Hu Anning; Zhu Bin

    2013-01-01

    Objective: To investigate the feasibility of setting mAs in liver enhanced CT scan according to plain scan noise with fixed mA CT scanner, in order to reduce the radiation dose. Methods: One hundred continuous patients underwent liver enhanced CT scan (group A) prospectively. Two hundred and fifty mAs was used in plain and enhanced CT scans. Noises of plain and venous phase CT images were measured, and the image quality was evaluated. The equation between mAs of enhanced scan and noise of plain scan image was derived. Another 100 continuous patients underwent liver enhanced CT scan (group B). Enhanced scan mAs was calculated from noise on plain scan by using the equation above. Noises on venous phase images were measured and the image quality was measured. Based on body mass index (BMI), patients in groups A and B were divided into three subgroups respectively: BMI < 18.5 kg/m 2 , 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 and BMI ≥ 25.0 kg/m 2 . Image quality score was compared with nonparametric rank sum test, CT dose index (CTDI) and effective dose (ED) were measured and compared between each subgroup with 2 independent samples t or t' test. Results: The equation between enhanced scan mAs (mAsX) and plain scan noise (SDp) was as follows: mAsX = mAs1 × [(0.989 × SDp + 1.06) /SDx] 2 , mAs1 = 250 mAs, SDx = 13. In patients with BMI < 18.5 kg/m 2 , ED of group A [(6.86 ± 0.38) mSv, n = 12] was significantly higher than group B [(2.66 ± 0.46) mSv, n = 10)] (t = 18.52, P < 0.01). In patients with 18.5 kg/m 2 ≤ BMI < 25.0 kg/m 2 , ED of group A [(7.08 ± 0.91) mSv, n = 66] was significantly higher than group B [(4.50 ± 1.41) mSv, n = 73] (t' = 10.57, P < 0.01). In patients with BMI ≥ 25.0 kg/m 2 , there was no significant difference between EDs of group A (7.54 ± 0.62 mSv, n = 22) and group B [(8.19 ± 3.16) mSv, n = 17] (t' = 0.89, P = 0.39). Image quality of 5 patients in group A and none in group B did not meet the diagnostic requirement

  8. Favorable noise uniformity properties of Fourier-based interpolation and reconstruction approaches in single-slice helical computed tomography

    International Nuclear Information System (INIS)

    La Riviere, Patrick J.; Pan Xiaochuan

    2002-01-01

    Volumes reconstructed by standard methods from single-slice helical computed tomography (CT) data have been shown to have noise levels that are highly nonuniform relative to those in conventional CT. These noise nonuniformities can affect low-contrast object detectability and have also been identified as the cause of the zebra artifacts that plague maximum intensity projection (MIP) images of such volumes. While these spatially variant noise levels have their root in the peculiarities of the helical scan geometry, there is also a strong dependence on the interpolation and reconstruction algorithms employed. In this paper, we seek to develop image reconstruction strategies that eliminate or reduce, at its source, the nonuniformity of noise levels in helical CT relative to that in conventional CT. We pursue two approaches, independently and in concert. We argue, and verify, that Fourier-based longitudinal interpolation approaches lead to more uniform noise ratios than do the standard 360LI and 180LI approaches. We also demonstrate that a Fourier-based fan-to-parallel rebinning algorithm, used as an alternative to fanbeam filtered backprojection for slice reconstruction, also leads to more uniform noise ratios, even when making use of the 180LI and 360LI interpolation approaches

  9. The Beatles, the Nobel Prize, and CT scanning of the chest.

    Science.gov (United States)

    Goodman, Lawrence R

    2010-01-01

    From its first test scan on a mouse, in 1967, to current medical practice, the CT scanner has become a core imaging tool in thoracic diagnosis. Initially financed by money from Beatles' record sales, the first patient scan was performed in 1971. Only 8 years later, a Nobel Prize in Physics and Medicine was awarded to Hounsfield and Cormack for their discovery. This article traces the history of CT scanner development and how each technical advance expanded chest diagnostic frontiers. Chest imaging now accounts for 30% of all CT scanning.

  10. Usefulness of the helical CT in gastro intestinally caused acute abdomen

    International Nuclear Information System (INIS)

    Cruz, R. A. de la; Martel, J.; Albillos, J. C.; Oliver, J. M.; Lopez, J.; Trapero, M. A.

    2000-01-01

    At present, there is a vivid debate on the role of the Helical CT (HCT) in the acute abdomen, principally on the usefulness of the non contrast HCT. We aim to present the most common semiological findings and the differential diagnoses, and to give a short description of the indications and protocols, according to the existing literature and to our experience with HCT during the last three years. We believe that the generalization of the use of HCT in emergencies avoid unnecessary surgery and shorten observation times on many occasions, with clear benefits in the clinical management of the patients. (Author) 30 refs

  11. Helical CT for lung-cancer screening. 3. Fundamental study for ultra-low-dose CT by application of small tube current and filter

    International Nuclear Information System (INIS)

    Itoh, Shigeki; Koyama, Shuji; Tusaka, Masatoshi; Maekoshi, Hisashi; Satake, Hiroko; Ishigaki, Takeo.

    1996-01-01

    In order to develop ultra-low-dose helical CT for lung cancer screening, the effect of reduction of the tube current to 20 mA and application of a 10 mm thick aluminium filter upon radiation dose and image quality was evaluated with a phantom. Exposure dose at the center of a gantry and absorbed dose at the center of an acrylic phantom at 20 mA with the filter were 15% and 29% of the dose at 50 mA without the filter, respectively. For reduction of absorbed dose, reduction of the tube current was more useful than application of the filter. Image noise at 20 mA with the filter was double that at 50 mA without the filter. Neither reduction of the tube current nor application of the filter changed full width at half maximum on section sensitivity of the Z-axis. Although reduction of the tube current did not affect the difference in CT values between an acrylic sphere and styroform, application of the filter caused a reduction of 4.5% in the difference in CT values. Neither reduction of the tube current nor application of the filter affected the contrast resolution of the high-contrast phantom; however, that of the low-contrast phantom deteriorated. Although improvement of the filter and evaluation of clinical images are necessary, reduction of the tube current to 20 mA and application of the aluminium filter appear to be a promising method for ultra-low-dose helical CT of the lung. (author)

  12. The use of CT scan in the pre-operative staging of bronchogenic carcinoma

    International Nuclear Information System (INIS)

    Pada, C.C.

    1992-01-01

    Surgery remains the treatment of choice in patients with localized bronchogenic carcinoma. Pre-operative identification of inoperability spares the patient from unnecessary surgery. This prospective study was carried out to determine the correctness of judgement regarding a patient's operability or inoperability based on the pre-operative staging of CT scan; to find out the sensitivity, specificity and overall accuracy of the CT scan in estimating tumor description, nodal status and metastatic spread to the chest. Staging was done by 3 senior radiologists aware of the diagnosis. Both the surgical and histopathologic findings and staging were gathered and used as measurement of truth in arriving at the CT scan's accuracy. Overall accuracy rate of CT scan in determining operability or inoperability is 80%; tumor description accuracy of assessment is 87% and nodal status estimation has an accuracy of 60%. Sensitivity of CT scan is assessment of metastatic spread to the chest is 93%. There is no statistically significant difference in the judgement of operability or interpretability by CT scan compared to surgical and histopathologic results. The CT scan is recommended as a valuable tool in the pre-operative staging of patients with bronchogenic carcinoma who are candidates for surgery. (auth.). 21 refs.; 8 tabs

  13. What are the potential advantages and disadvantages of volumetric CT scanning?

    Science.gov (United States)

    Voros, Szilard

    2009-01-01

    After the introduction and dissemination of 64-slice multislice computed tomography systems, cardiovascular CT has arrived at a crossroad, and different philosophies lead down different paths of technologic development. Increased number of detector rows in the z-axis led to the introduction of dynamic, volumetric scanning of the heart and allows for whole-organ imaging. Dynamic, volumetric "whole-organ" scanning significantly reduces image acquisition time; "single-beat whole-heart imaging" results in improved image quality and reduced radiation exposure and reduced contrast dose. It eliminates helical and pitch artifacts and allows for simultaneous imaging of the base and apex of the heart. Beyond coronary arterial luminal imaging, such innovations open up the opportunity for myocardial perfusion and viability imaging and coronary arterial plaque imaging. Dual-source technology with 2 x-ray tubes placed at 90-degree angles provides heart rate-independent temporal resolution and has the potential for tissue characterization on the basis of different attenuation values at different energy levels. Refined detector technology allows for improved low-contrast resolution and may be beneficial for more detailed evaluation of coronary arterial plaque composition. The clinical benefit of each of these technologies will have to be evaluated in carefully designed clinical trials and in everyday clinical practice. Such combined experience will probably show the relative benefit of each of these philosophies in different patient populations and in different clinical scenarios.

  14. Complete opacification of the esophageal lumen using helical (slip-ring) CT scanner with cellulose-barium paste, and its application to the evaluation of the effect of radiation therapy for esophageal cancer

    International Nuclear Information System (INIS)

    Noda, Yoshihiro; Ogawa, Yasuhiro; Nishioka, Akihito; Inomata, Taisuke; Yoshida, Shoji; Toki, Taiichi; Ogoshi, Shohei

    1996-01-01

    The esophageal lumen of patients with esophageal cancer or paraesophageal disorders is frequently impossible to visualize on CT image and, consequently, difficulties in the differentiation of esophageal tumor mass and adjacent organs are often encountered. Therefore, we have developed a safe, high viscous, oral contrast medium which contains carboxy-methyl cellulose sodium (a conventionally used laxative with mild effect and inexpensive) and low-density 2% barium. Helical CT scan using this medium plus intravenous injection of iodine contrast enhancement agent was performed in 24 patients with esophageal cancer or paraesophageal diseases. Complete opacification of the esophageal lumen was obtained for almost all images of the upper, middle and lower thoracic esophagus. This method is easy to use and has not caused any serious side effect so far. We have developed a new oral contrast agent for esophageal helical CT to estimate the volume of tumor on CT images before and after treatment. The therapeutic effect of radiotherapy in 10 patients with esophageal cancer was evaluated using this method. In seven of the 10 patients, the rate of decrease of the esophageal tumor mass during radiotherapy was much lower with our new method than with conventionally used method. Combination of these two methods is essential for the evaluation of the therapeutic effect of radiotherapy for esophageal cancer. (author)

  15. Full-Body CT Scans - What You Need to Know

    Science.gov (United States)

    ... Procedures Medical Imaging Medical X-ray Imaging Full-Body CT Scans - What You Need to Know Share ... if you are thinking of having a whole-body screening: Whole-body CT screening has not been ...

  16. Evolution of traumatic intracerebral hematoma. Analysis of sequential CT scans since per-acute stage

    Energy Technology Data Exchange (ETDEWEB)

    Nagaseki, Yoshishige; Horikoshi, Satoru [Gunma Univ., Maebashi (Japan). School of Medicine; Tamura, Masaru

    1984-05-01

    To clarify the evolution of traumatic intracerebral hematoma (TICH), initial computerized tomography (CT) scans of 28 TICH cases performed within one hour after head trauma were studied along with their follow-up CT scans. They were classified into the following two groups; per-acute group included seven cases in which TICH was completed on the initial CT scans taken within one hour after head injury and acute group included 21 cases in which the initial CT scans revealed isodensity or high density spot and repeat CT scans disclosed TICH by 48 hours after injury. In the per-acute group, initial CT scans showed a homogeneous, well defined, and high density mass (1.5-6.5 cm in diameter). In sequential CT scans of the three cases, the hematoma did not increase but spontaneously disappeared. Other four cases died early after head trauma. Their initial CT scans revealed a large high density mass (3-6.5 cm in diameter) combined with other extracerebral hemorrhages. In the acute group, initial CT scans demonstrated isodensity or high density spot and sequential CT scans showed mottled appearance of salt and pepper appearance, and after a while showed fusion of small high density areas to become a massive high density area (contusional hematoma) by 48 hours after injury. In six cases of this group, the contusional hematoma was removed within 24 hours after injury and in one case at 3.5 days. In other 14 cases, the hematomas shrank or disappeared spontaneously. From these results, it was considered that evolution of TICH's were classified into the two groups; per-acute group resulting from rupture of vessels and acute group resulting from contusion.

  17. Study on children patient dose in single-detector and multi-detector row helical computed tomography

    International Nuclear Information System (INIS)

    Lu Heqing; Zhu Guoying; Zhuo Weihai; Liu Haikuan; Guo Changyi

    2008-01-01

    Objective: To study and evaluate the radiation dose of children patient in single-detector and multi-detector row helical CT scan. Methods: The head and body CT dose index of 21 CT scanners were tested. Then the values of CTDI w , CTDI vol and DLP were calculated combining with the parameters of routine head and chest scan for children of 0-1 year old group, 5 years old group, 10 years old group and adults. The effective doses of children of every age group and adults in routine head and chest scan were subsequently estimated from effective dose per DLP by age and the calculated values of DLP. Results: CTDI per mAs is greater in the head than that in the body. In head routine scan, the effective doses of 0-1 year old group,5 years old group and 10 year old group were 2.2, 1.3 and 1.1 mSv, respectively. In chest routine scan, the effective doses of 0-1 year old group,5 years old group and 10 years old group were 5.3, 3.1 and 3.4 mSv, respectively. Effective doses to children per mAs are equally 1.8 times higher than corresponding values for adults. The CTDI vol , DLP and effective dose to children in head routine scan for MDCT were greater those that for single-detector CT and dual- detector CT. The CTDI vol , DLP and effective dose to children in chest routine scan for MDCT and dual-detector row CT were smaller than that for single-detector row CT. Conclusions: Children me more radiation risk in CT examination as compared with adults. So we should strictly abide by justification of children CT examination, and optimize the parameters of CT scan rationally in order to reduce the radiation dose to children patient as much as possible. (authors)

  18. Socio-economic variation in CT scanning in Northern England, 1990-2002

    Directory of Open Access Journals (Sweden)

    Pearce Mark S

    2012-01-01

    Full Text Available Abstract Background Socio-economic status is known to influence health throughout life. In childhood, studies have shown increased injury rates in more deprived settings. Socio-economic status may therefore be related to rates of certain medical procedures, such as computed tomography (CT scans. This study aimed to assess socio-economic variation among young people having CT scans in Northern England between 1990 and 2002 inclusive. Methods Electronic data were obtained from Radiology Information Systems of all nine National Health Service hospital Trusts in the region. CT scan data, including sex, date of scan, age at scan, number and type of scans were assessed in relation to quintiles of Townsend deprivation scores, obtained from linkage of postcodes with census data, using χ2 tests and Spearman rank correlations. Results During the study period, 39,676 scans were recorded on 21,089 patients, with 38,007 scans and 19,485 patients (11344 male and 8132 female linkable to Townsend scores. The overall distributions of both scans and patients by quintile of Townsend deprivation scores were significantly different to the distributions of Townsend scores from the census wards included in the study (p Conclusions Social inequalities exist in the numbers of young people undergoing CT scans with those from deprived areas more likely to do so. This may reflect the rates of injuries in these individuals and implies that certain groups within the population may receive higher radiation doses than others due to medical procedures.

  19. 4D-CT scans reveal reduced magnitude of respiratory liver motion achieved by different abdominal compression plate positions in patients with intrahepatic tumors undergoing helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yong, E-mail: hu.yong@zs-hospital.sh.cn; Zhou, Yong-Kang, E-mail: zhouyk2009@163.com; Chen, Yi-Xing, E-mail: chen.yixing@zs-hospital.sh.cn; Shi, Shi-Ming, E-mail: shiming32@126.com; Zeng, Zhao-Chong, E-mail: zeng.zhaochong@zs-hospital.sh.cn [Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180 Feng Lin Road, Shanghai 200032 (China)

    2016-07-15

    Purpose: While abdominal compression (AC) can be used to reduce respiratory liver motion in patients receiving helical tomotherapy for hepatocellular carcinoma, the nature and extent of this effect is not well described. The purpose of this study was to evaluate the changes in magnitude of three-dimensional liver motion with abdominal compression using four-dimensional (4D) computed tomography (CT) images of several plate positions. Methods: From January 2012 to October 2015, 72 patients with intrahepatic carcinoma and divided into four groups underwent 4D-CT scans to assess respiratory liver motion. Of the 72 patients, 19 underwent abdominal compression of the cephalic area between the subxiphoid and umbilicus (group A), 16 underwent abdominal compression of the caudal region between the subxiphoid area and the umbilicus (group B), 11 patients underwent abdominal compression of the caudal umbilicus (group C), and 26 patients remained free breathing (group D). 4D-CT images were sorted into ten-image series, according to the respiratory phase from the end inspiration to the end expiration, and then transferred to treatment planning software. All liver contours were drawn by a single physician and confirmed by a second physician. Liver relative coordinates were automatically generated to calculate the liver respiratory motion in different axial directions to compile the 10 ten contours into a single composite image. Differences in respiratory liver motion were assessed with a one-way analysis of variance test of significance. Results: The average respiratory liver motion in the Y axial direction was 4.53 ± 1.16, 7.56 ± 1.30, 9.95 ± 2.32, and 9.53 ± 2.62 mm in groups A, B, C, and D, respectively, with a significant change among the four groups (p < 0.001). Abdominal compression was most effective in group A (compression plate on the subxiphoid area), with liver displacement being 2.53 ± 0.93, 4.53 ± 1.16, and 2.14 ± 0.92 mm on the X-, Y-, and Z

  20. The pictures of CT scan of gold pneumonitis

    International Nuclear Information System (INIS)

    Taguchi, Yoshio; Iwata, Takekuni; Kuroda, Yasumasa; Sadato, Norihiro; Tanemoto, Kiichiro; Adachi, Kazuhiko.

    1987-01-01

    We experienced two cases of gold pneumonitis and their interesting findings of CT scan. After the cessation of gold salt, both cases were treated with the corticosteroid, resulting in the disappearance of pulmonary manifestations and clearing of shadows on chest roentgenograms. The findings of CT scan on both cases were very interesting. They were the high density shadows along the bronchovascular bundles, the fluffy figures surroundings these shadows and band like shadows reached to the thoracic wall. We considered that each shadows were pathologically compatible with severe exudative changes of interstitial pneumonitis, shrinkage surroundings them and thickness of interlobular septum. (author)

  1. Optimized enhancement in helical CT: Experiences with a real-time bolus tracking system in 628 patients

    International Nuclear Information System (INIS)

    Kirchner, J.; Kickuth, R.; Laufer, U.; Noack, M.; Liermann, D.

    2000-01-01

    AIMS: Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. MATERIALS AND METHODS: In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140 kV, 43 mA, TI 0.5 s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100 HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. RESULTS: There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27 s (range 13-67 s) and only 65 ml (range 41-105 ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21 s (range 12-48 s) and the mean amount of administered contrast medium was 48 ml (range 38-71 ml). CONCLUSION: Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration. Kirchner, J. (2000). Clinical Radiology 55, 368-373

  2. Optimized enhancement in helical CT: experiences with a real-time bolus tracking system in 628 patients.

    Science.gov (United States)

    Kirchner, J; Kickuth, R; Laufer, U; Noack, M; Liermann, D

    2000-05-01

    Ultrafast detector technology enables bolus-triggered application of contrast media. In a prospective study we investigated the benefit of this new method with the intention of optimizing enhancement during examination of the chest and abdomen. In total, we examined 548 patients under standardized conditions. All examinations were performed on a Somatom Plus 4 Power CT system (Siemens Corp., Forchheim, Germany) using the CARE-Bolus software. This produces repetitive low-dose test images (e.g. for the lung: 140 kV, 43 mA, TI 0.5 s) and measures the Hounsfield attenuation in a pre-selected region of interest. After exceeding a defined threshold, a diagnostic spiral CT examination was begun automatically. The data obtained from 321 abdominal CT and 179 lung CT examinations were correlated with different parameters such as age, weight and height of the patients and parameters of vascular access. In a group of 80 patients, the injection of contrast medium was stopped after reaching a pre-defined threshold of an increase of 100 HU over the baseline. Then, we assessed the maximal enhancement of liver, pulmonal artery trunk and aortic arch. There was no correlation between bolus geometry and age, body surface or weight. In helical CT of the abdomen the threshold was reached after a mean trigger time of 27 s (range 13-67 s) and only 65 ml (range 41-105 ml) of contrast medium were administered. In helical CT of the lung the threshold was reached after 21 s (range 12-48 s) and the mean amount of administered contrast medium was 48 ml (range 38-71 ml). Bolus triggering allows optimized enhancement of the organs and reduces the dose of contrast material required compared with standard administration. Copyright 2000 The Royal College of Radiologists.

  3. Automated lung volumetry from routine thoracic CT scans: how reliable is the result?

    Science.gov (United States)

    Haas, Matthias; Hamm, Bernd; Niehues, Stefan M

    2014-05-01

    Today, lung volumes can be easily calculated from chest computed tomography (CT) scans. Modern postprocessing workstations allow automated volume measurement of data sets acquired. However, there are challenges in the use of lung volume as an indicator of pulmonary disease when it is obtained from routine CT. Intra-individual variation and methodologic aspects have to be considered. Our goal was to assess the reliability of volumetric measurements in routine CT lung scans. Forty adult cancer patients whose lungs were unaffected by the disease underwent routine chest CT scans in 3-month intervals, resulting in a total number of 302 chest CT scans. Lung volume was calculated by automatic volumetry software. On average of 7.2 CT scans were successfully evaluable per patient (range 2-15). Intra-individual changes were assessed. In the set of patients investigated, lung volume was approximately normally distributed, with a mean of 5283 cm(3) (standard deviation = 947 cm(3), skewness = -0.34, and curtosis = 0.16). Between different scans in one and the same patient the median intra-individual standard deviation in lung volume was 853 cm(3) (16% of the mean lung volume). Automatic lung segmentation of routine chest CT scans allows a technically stable estimation of lung volume. However, substantial intra-individual variations have to be considered. A median intra-individual deviation of 16% in lung volume between different routine scans was found. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  4. Spontaneous spinal epidural hematoma diagnosed by CT scan

    International Nuclear Information System (INIS)

    Abumiya, Takeo; Isu, Toyohiko; Iwasaki, Yoshinobu; Akino, Minoru; Abe, Hiroshi

    1985-01-01

    A case of spinal epidural hematoma diagnosed by CT scan is reported. A 58-year-old man was admitted on June 18, 1984. He had had a sudden onset of severe low-back pain 7 days before admission and had developed paraparesis and numbness of the lower limbs 4 day before admission. Physical examination revealed weakness in the lower limbs, with the reflexes there decreased. The Babinski reflex and the Chaddock reflex were, however, present on both sides. Sensory disturbances were noted below L 2 . Urinary incontinence was present, too. Metrizamide myelography revealed an epidural mass which was located from the power part of T 11 to the upper part of L 2 . A CT scan revealed a biconvex, relatively high-density mass in the posterior spinal canal. On the day of admission, a laminectomy was performed from T 11 to L 1 , and the epidural hematoma was evacuated. The postoperative course was uneventful. Spinal epidural hematoma is uncommon. A CT scan can be used for an early diagnosis of this lesion. According to the review of the CT findings in 15 reported cases, including our case, CT reveals a smoothly marginated biconvex homogeneous density mass. The density of the hematoma decreases with the time. An acute type (within 3 days) is high-density, while a chronic type has a relatively high or isodensity. The acute type is easily differentiated from other epidural masses, such as a herniated disc, an epidural abscess, and an epidural tumor. On the other hand, the diagnosis of the chronic type is not always easy. (author)

  5. Serial CT scans and Menkes' kinky hair disease

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Eizo; Kameyama, Junji; Yoshimitsu, Hajime; Mori, Mikio; Tanaka, Mutsuo; Yoshimitsu, Kazunori.

    1988-02-01

    Menkes' kinky hair disease is a sex-linked recessive disorder of copper metabolism, characterized by progressive psychomotor deterioration, seizures, and peculiar hair structure. We examined serial CT scans of patients with this disease. A 2,210-g male infant was delivered after an uneventful gestation of 36 weeks. His one-minute Apgar score was 9. His uncle had died at 1 year of age. His first cousin was also diagnosed as having Menkes' kinky hair disease when our patient was 2 years old. Shortly after birth he had mild respiratory distress. At 5 days of age, he developed setting-sun signs. The first CT scan, at 10 days of age, revealed mild posterior fossa hemorrhages. At 3 months of age, myoclonic seizures began, and the CT scan revealed subdural effusion and mild brain atrophy. The seizures were controllable by using phenobarbital, valproic acid, and nitrazepam. He did not follow light or a fixate, but the fundi were normal. He was diffusely hypotonic. At 9 months of age, the seizures became uncontrollable. The CT scans at 15 and 31 months of age showed subdural hemorrhage and/or brain atrophy. At 15 months of age, the serum copper level was 42 ..mu.. g/dl, while the serum ceruloplasmin level was 3.2 mg/dl. He exhibited severe developmental failure. At 4 years of age, he died.

  6. CT Scanning in Identification of Sheep Cystic Echinococcosis.

    Science.gov (United States)

    Mao, Rui; Qi, Hongzhi; Pei, Lei; Hao, Jie; Dong, Jian; Jiang, Tao; Ainiwaer, Abudula; Shang, Ge; Xu, Lin; Shou, Xi; Zhang, Songan; Wu, Ge; Lu, Pengfei; Bao, Yongxing; Li, Haitao

    2017-01-01

    We aim to determine the efficiency of CT in identification of cystic echinococcosis in sheep. Fifty-three sheep with liver cysts confirmed by ultrasonography were subject to CT scan to evaluate the number, size, and type of the cysts in liver and lung, confirmed using necropsy. The correlation of numbers between liver cysts and lung cysts was calculated using Pearson analysis. Necropsy indicated a 98% consensus on size, location, number, and activity compared with CT scan. The viable cysts were 53.1% and 50.6% in the liver and lung, respectively. Among the cysts in liver, 35.5%, 9.5%, 5.7%, 10.2%, and 39.1% were Types CE1, CE2, CE3, CE4, and CE5, respectively. The cysts in the lungs, 17.4%, 26.9%, 12.1%, 11.6%, and 32.1%, were Types CE1, CE2, CE3, CE4, and CE5, respectively. A significant correlation was noticed between the number of cysts in liver and those in lung ( R = 0.770, P < 0.001). CT scan is a suitable tool in determining the size and type of cystic hydatid cysts in both liver and lung of sheep. A significant correlation was noticed between the numbers in liver and lung, indicating that lung infection was likely due to the expansion of liver cyst burden pressure.

  7. Post-operative abdominal CT scanning in extrahepatic biliary atresia

    Energy Technology Data Exchange (ETDEWEB)

    Day, D L; Mulcahy, P F; Letourneau, J G; Dehner, L P

    1989-07-01

    A retrospective review of the abdominal CT scans of 26 children with extrahepatic biliary atresia was performed, and the results were correlated with available surgical and pathologic data. Associated congenital anomalies or acquired abnormalities were identified in these patients. Congenital anomalies included polysplenia, venous anomalies and bowel stenosis. Acquired abnormalities developed secondary to cirrhosis, portal hypertension, intrahepatic biliary duct dilatation, and hepatic ischemia. Despite frequent episodes of ascending cholangitis in these children, no hepatic abscesses were identified by CT or by pathologic examination. In conclusion, abdominal CT scanning of children with extrahepatic biliary atresia can define congenital and acquired abnormalities and provide important anatomic data for the surgeons before liver transplantation. (orig.).

  8. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    International Nuclear Information System (INIS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-01-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens

  9. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    Science.gov (United States)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  10. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alva-Sánchez, Héctor, E-mail: halva@ciencias.unam.mx [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico); Reynoso-Mejía, Alberto [Unidad de Imagen Molecular PET/CT, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F., Mexico and Departamento de Neuroimagen, Instituto Nacional de (Mexico); Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús [Departamento de Neuroimagen, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Insurgentes Sur 3877 Col. La Fama, 14269, México D.F. (Mexico)

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  11. Colon distension and scan protocol for CT-colonography: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, Thierry N., E-mail: t.n.boellaard@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Haan, Margriet C. de, E-mail: m.c.dehaan@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Venema, Henk W., E-mail: h.w.venema@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands); Stoker, Jaap, E-mail: j.stoker@amc.uva.nl [Department of Radiology, Academic Medical Center, University of Amsterdam, PB 22660, 1100 DD Amsterdam (Netherlands)

    2013-08-15

    This article reviews two important aspects of CT-colonography, namely colonic distension and scan parameters. Adequate distension should be obtained to visualize the complete colonic lumen and optimal scan parameters should be used to prevent unnecessary radiation burden. For optimal distension, automatic carbon dioxide insufflation should be performed, preferably via a thin, flexible catheter. Hyoscine butylbromide is – when available – the preferred spasmolytic agent because of the positive effect on insufflation and pain/burden and its low costs. Scans in two positions are required for adequate distension and high polyp sensitivity and decubitus position may be used as an alternative for patients unable to lie in prone position. The great intrinsic contrast between air or tagging and polyps allows the use of low radiation dose. Low-dose protocol without intravenous contrast should be used when extracolonic findings are deemed unimportant. In patients suspected for colorectal cancer, normal abdominal CT scan protocols and intravenous contrast should be used in supine position for the evaluation of extracolonic findings. Dose reduction can be obtained by lowering the tube current and/or voltage. Tube current modulation reduces the radiation dose (except in obese patients), and should be used when available. Iterative reconstructions is a promising dose reducing tool and dual-energy CT is currently evaluated for its applications in CT-colonography. This review also provides our institution's insufflation procedure and scan parameters.

  12. Value of contrast enhanced CT scanning in the non-trauma emergency room patient

    International Nuclear Information System (INIS)

    Wood, L.P.; Parisi, M.; Finch, I.J.

    1990-01-01

    To determine the value of performing contrast CT in addition to non-contrast CT in the evaluation of acute non-traumatic central nervous system disorders, we retrospectively reviewed 322 cases originating from the emergency room at our institution. The most common indication for scanning was seizure activity (34% of total), followed by headache (30%), focal neurological deficit (10%), and altered mental status (8%). 75% of the noncontrast scans were normal. The contrast enhanced scan revealed abnormalities not evident on the non-contrast scan in only three of these cases, and the information did not alter patient management. We conclude that in the acute setting, if a non-contrast CT is normal, a contrast study is usually unnecessary. Therefore, given the additional risks of contrast infusion, the contrast study, if needed, is generally best obtained at a later date, after more careful evaluation of the patient's history and medical records. If the non-contrast CT scan is abnormal, a contrast enhanced CT scan may be beneficial, but, again, is often not needed to direct acute patient management. (orig.)

  13. Influence of gantry angle in helical computed tomography. Usefullness of 1-dimension sharpness filter

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Hirofumi; Suzuki, Toru; Matsuura, Shigeru; Kai, Tsuyoshi; Shimizu, Toshiyuki [Hyuga Hospital of Saiseikai Foundation, Kadogawa, Miyazaki (Japan)

    2001-05-01

    When we let gantry tilt and do scan in helical CT, vertical sharpness deteriorates. We were able to revise it with 1-dimensional sharpness filter which the square sum of difference of MTF was compared, and was designed this time. And the unsharpness was in proportion to sin of gantry angle. As a result, we led several sets of frequency emphasis degree. There is a model to built 1-dimension sharpness filter in a scan plan. It is useful for clinical diagnoses. (author)

  14. Influence of gantry angle in helical computed tomography. Usefullness of 1-dimension sharpness filter

    International Nuclear Information System (INIS)

    Kawano, Hirofumi; Suzuki, Toru; Matsuura, Shigeru; Kai, Tsuyoshi; Shimizu, Toshiyuki

    2001-01-01

    When we let gantry tilt and do scan in helical CT, vertical sharpness deteriorates. We were able to revise it with 1-dimensional sharpness filter which the square sum of difference of MTF was compared, and was designed this time. And the unsharpness was in proportion to sin of gantry angle. As a result, we led several sets of frequency emphasis degree. There is a model to built 1-dimension sharpness filter in a scan plan. It is useful for clinical diagnoses. (author)

  15. CT scan of bacterial and aseptic meningitis

    International Nuclear Information System (INIS)

    Takemoto, Kazumasa; Saiwai, Shigeo; Tamaoka, Koichi

    1983-01-01

    CT scans of the patients with aseptic and bacterial meningitis were reviewed and compared to previous reports. In aseptic meningitis, no abnormal CT findings were observed. In bacterial meningitis, CT findings were ventricular dilatation, subdural fluid collection, parenchymal low density, intracerebral hematoma and meningeal enhancement after contrast injection. Three patients among 48 suffered from status epileptics during the course of the illness. All of 3 patients developed parenchymal inhomogeneous low density and progressive ventricular dilatation which did not improve after ventricular peritoneal shunt surgery. We believe that these changes are most likely due to hypoxic hypoxemia during epileptic seizure and meningitis itself seems to play a little role. (author)

  16. The efficacy of low-dose helical CT screening as an option for health examination

    International Nuclear Information System (INIS)

    Kishi, Kazuma; Hara, Shigeko; Kurosaki, Atsuko; Fujii, Takeshi; Yoshimura, Kunihiko

    2007-01-01

    We retrospectively evaluated the results of low-dose helical CT screening as an option for health examinations. From November 2002 to October 2005, CT screening was performed in 2,306 individuals (men 1,766, women 540, mean age 56.1 years). Among them, 71 individuals (3.1%) were diagnosed as having active thoracic diseases consisting of 14 neoplasms and 57 non-neoplastic diseases. Of 14 patients with neoplastic lesions, 13 had lung cancer, 1 of whom had double primary lung cancer, and 1 had atypical adenomatous hyperplasia. The mean diameter of the 14 lung cancers was 14.4 mm. The histology of these lesions was adenocarcinoma in 13 and squamous cell carcinoma in 1. The pathological stage was IA in 12 patients and IIA in 1. All patients underwent surgical resection. On the other hand, emphysema was diagnosed in 40 asymptomatic individuals based on CT and spirometry, and smoking cessation was strongly implemented for those who were current smokers. CT screening is useful for detecting not only early lung cancer but also non-neoplastic lung diseases. (author)

  17. Synchronized control of spiral CT scan for security inspection device

    International Nuclear Information System (INIS)

    Wang Jue; Jiang Zenghui; Wang Fuquan

    2008-01-01

    In security inspection system of spiral CT, the synchronization between removing and rotating, and the scan synchronization between rotating and sampling influence quality of image reconstruction, so it is difficulty and important that how to realize synchronized scan. According to the controlling demand of multi-slice Spiral CT, the method to realize synchronized scan is given. a synchronized control system is designed, in which we use a industrial PC as the control computer, use magnetic grids as position detectors, use alternating current servo motor and roller motor as drivers respectively drive moving axis and rotating axis. This method can solve the problem of synchronized scan, and has a feasibility and value of use. (authors)

  18. Detailed Review of CT Scans Aids Assessment of the Airway in ...

    African Journals Online (AJOL)

    Two cases are presented that illustrate the importance of information gained from CT scans of the head and neck taken in patients presenting for maxillo-facial surgery. The first case involved a 25 year old with a massive tumour filling his mouth. Pre-operative assessment was done without reviewing the CT scans of his ...

  19. Radiation exposure distribution in patients undergoing CT brain scans

    International Nuclear Information System (INIS)

    Yang Zhanshan; Feng Dinghua; Chang Zichi; Li Shijun

    1989-12-01

    The distribution of surface exposures in patients undergoing single and multiple computerized tomographic brain scans with Hitachi CT-W500 was measured by LiF(Mg, Ti) thermoluminescent dosimetry. It was found that there was no significant difference in the sufrace exposures from different scanning slices. However, the exposure doses at different scanning angles around the head were different significantly. The reference point of the maximum surface exposure was at the temporal part of the head. the maximum surface exposure was at 1.65 x 10 -3 C·kg -1 while the average exposure was 1.55 x 10 -3 C·kg -1 . The ratio of the average dose resulting from nine scans to that from a single scan was 1.3, and the surface exposure contribution of scattered radiation was computed. At the same time the radiation doses to eyes, thyroid, chest and gonads of patiens at corresponding position were also measured and were compared with those from CT cranial scans in children and skull radiographic procedures respectively

  20. Evaluation of Image Quality in Low Tube-Voltage Chest CT Scan

    International Nuclear Information System (INIS)

    Kim, Hyun Ju; Cho, Jae Hwan; Park, Cheol Soo

    2010-01-01

    The patients who visited this department for pulmonary disease and need CT scans for Follow-up to observe change of CT value, evaluation of image quality and decrease of radiation dose as change of kVp. Subjects were the patients of 20 persons visited this department for pulmonary disease and Somatom Sensation 16(Semens, Enlarge, Germany) was used. Measurement of CT value as change of kVp was done by setting up ROI diameter of 1cm at the height of thyroid, aortic arch, right pulmonary artery in arterial phase image using 100 kVp, measuring 3 times, and recorded the average. CT value of phantom was measured by scanning phantoms which means contrast media diluted by normal saline by various ratio with tube voltage of 80 kVp, 100 kVp, 120 kVp, 140 kVp and recorded the average of 3 CT values of center of phantom image. In analysing radiation dose, CTDIVOL values of the latest arterial phase image of 120 kVp and as this research set that of 100 kVp were analyzed comparatively. 2 observers graded quality of chest images by 5 degrees (Unacceptable, Suboptimal, Adequate, Good, Excellent). CT value of chest image increased at 100 kVp by 14.06%∼27.26% in each ROI than 120 kVp. CT value of phantom increased as tube voltage lowered at various concentration of contrast media. CTDIVOL decreased at 100 kVp(5.00 mGy) by 36% than 120 kVp(7.80 mGy) in radiation dose analysis. here were 0 Unacceptable, 1 Suboptimal, 3 Adequate, 10 Good, 6 Excellent in totally 20 persons. Chest CT scanning with low kilo-voltage for patients who need CT scan repeatedly can bring images valuable for diagnose, and decrease radiation dose against patients

  1. CT study of pancreatic diseases with modified dynamic scanning

    International Nuclear Information System (INIS)

    Qian Minghui; Zhu Guangying

    1990-01-01

    Experience of 20 cases modified dynamic CT scanning is presented. With a slight increased X-ray tube burden, it is possible to investigate tumor blood supply and find small pancreatic insulinoma with this method. The capsular sign typical for chronic traumatic pancreatic hematoma on CT is presented

  2. Developing optimized CT scan protocols: Phantom measurements of image quality

    International Nuclear Information System (INIS)

    Zarb, Francis; Rainford, Louise; McEntee, Mark F.

    2011-01-01

    Purpose: The increasing frequency of computerized tomography (CT) examinations is well documented, leading to concern about potential radiation risks for patients. However, the consequences of not performing the CT examination and missing injuries and disease are potentially serious, impacting upon correct patient management. The ALARA principle of dose optimization must be employed for all justified CT examinations. Dose indicators displayed on the CT console as either CT dose index (CTDI) and/or dose length product (DLP), are used to indicate dose and can quantify improvements achieved through optimization. Key scan parameters contributing to dose have been identified in previous literature and in previous work by our group. The aim of this study was to optimize the scan parameters of mA; kV and pitch, whilst maintaining image quality and reducing dose. This research was conducted using psychophysical image quality measurements on a CT quality assurance (QA) phantom establishing the impact of dose optimization on image quality parameters. Method: Current CT scan parameters for head (posterior fossa and cerebrum), abdomen and chest examinations were collected from 57% of CT suites available nationally in Malta (n = 4). Current scan protocols were used to image a Catphan 600 CT QA phantom whereby image quality was assessed. Each scan parameter: mA; kV and pitch were systematically reduced until the contrast resolution (CR), spatial resolution (SR) and noise were significantly lowered. The Catphan 600 images, produced by the range of protocols, were evaluated by 2 expert observers assessing CR, SR and noise. The protocol considered as the optimization threshold was just above the setting that resulted in a significant reduction in CR and noise but not affecting SR at the 95% confidence interval. Results: The limit of optimization threshold was determined for each CT suite. Employing optimized parameters, CTDI and DLP were both significantly reduced (p ≤ 0.001) by

  3. Multi-detector row helical CT of the liver. Quantitative assessment of iodine concentration of intravenous contrast material on multiphasic CT. A prospective randomized study

    International Nuclear Information System (INIS)

    Tsurusaki, Masakatsu; Sugimoto, Koji; Fujii, Masahiko; Sugimura, Kazuro

    2004-01-01

    The purpose of this study was to assess the quantitative effects of contrast material concentration on hepatic parenchymal and vascular enhancement in multiphasic computed tomography (CT), using multi-detector row helical CT. We designed a prospective randomized study to test two different concentrations of contrast material on five phasic scans of the liver. One hundred patients were randomly assigned to two groups: an iodine concentration of 300 mg/mL in group A and 370 mg/mL in group B. All patients received a fixed volume of 100 mL at a 4 mL/sec injection rate. Enhancement values for the hepatic parenchyma and aorta at three levels (upper, middle, and lower level of the liver), and values for portal and hepatic veins were statistically compared between the two groups. Hepatic parenchymal enhancement values at all levels of the liver in portal phase (PP) and equilibrium phase (EP) were significantly higher in group B than in group A (p<0.01). Aortic enhancement values at two levels of the liver (middle and lower) in early hepatic arterial phase (EAP) were significantly higher in group B than in group A (p<0.05), however, there was no significant difference between groups A and B in aortic enhancement during the delayed hepatic arterial phase (DAP). Portal and hepatic venous enhancement values in PP and EP were significantly higher in group B than in group A (p<0.01). On multiphasic dynamic CT, the use of a higher iodine concentration of contrast material results in higher hepatic parenchymal enhancement and aortic enhancement, as well as higher portal and hepatic venous enhancement. (author)

  4. A BPF-FBP tandem algorithm for image reconstruction in reverse helical cone-beam CT

    International Nuclear Information System (INIS)

    Cho, Seungryong; Xia, Dan; Pellizzari, Charles A.; Pan Xiaochuan

    2010-01-01

    Purpose: Reverse helical cone-beam computed tomography (CBCT) is a scanning configuration for potential applications in image-guided radiation therapy in which an accurate anatomic image of the patient is needed for image-guidance procedures. The authors previously developed an algorithm for image reconstruction from nontruncated data of an object that is completely within the reverse helix. The purpose of this work is to develop an image reconstruction approach for reverse helical CBCT of a long object that extends out of the reverse helix and therefore constitutes data truncation. Methods: The proposed approach comprises of two reconstruction steps. In the first step, a chord-based backprojection-filtration (BPF) algorithm reconstructs a volumetric image of an object from the original cone-beam data. Because there exists a chordless region in the middle of the reverse helix, the image obtained in the first step contains an unreconstructed central-gap region. In the second step, the gap region is reconstructed by use of a Pack-Noo-formula-based filteredbackprojection (FBP) algorithm from the modified cone-beam data obtained by subtracting from the original cone-beam data the reprojection of the image reconstructed in the first step. Results: The authors have performed numerical studies to validate the proposed approach in image reconstruction from reverse helical cone-beam data. The results confirm that the proposed approach can reconstruct accurate images of a long object without suffering from data-truncation artifacts or cone-angle artifacts. Conclusions: They developed and validated a BPF-FBP tandem algorithm to reconstruct images of a long object from reverse helical cone-beam data. The chord-based BPF algorithm was utilized for converting the long-object problem into a short-object problem. The proposed approach is applicable to other scanning configurations such as reduced circular sinusoidal trajectories.

  5. Low-dose ECG-gated 64-slices helical CT angiography of the chest: evaluation of image quality in 105 patients

    International Nuclear Information System (INIS)

    D'Agostino, A.G.; Remy-Jardin, M.; Khalil, C.; Remy, J.; Delannoy-Deken, V.; Duhamel, A.; Flohr, T.

    2006-01-01

    The purpose of this study was to evaluate image quality of low-dose electrocardiogram (ECG)-gated multislice helical computed tomography (CT) angiograms of the chest. One hundred and five consecutive patients with a regular sinus rhythm (72 men; 33 women) underwent ECG-gated CT angiographic examination of the chest without administration of beta blockers using the following parameters: (a) collimation 32 x 0.6 mm with z-flying focal spot for the acquisition of 64 overlapping 0.6-mm slices, rotation time 0.33 s, pitch 0.3; (b) 120 kV, 200 mAs; (c) use of two dose modulation systems, including adjustment of the mAs setting to the patient's size and anatomical shape and an ECG-controlled tube current. Subjective and objective image quality was evaluated by two radiologists in consensus on 3-mm-thick scans reconstructed at 55% of the response rate (RR) interval. The population and protocol characteristics included: (a) a mean [±standard deviation (SD)] body mass index (BMI) of 24.47 (±4.64); (b) a mean (±SD) heart rate of 72.04 (±15.76) bpm; (c) a mean (±SD) scanning time of 18.3 (±2.73) s; (d) a mean (±SD) dose-length product (DLP) value of 260.57 (±83.67) mGy/cm; (e) an estimated average effective dose of 4.95 (±1.59) mSv. Subjective noise was depicted in a total of nine examinations (8.5%), always rated as mild. Objective noise was assessed by measuring the standard deviation of pixel values in a homogeneous region of interest within the trachea and descending aorta; SD was 15.91 HU in the trachea and 22.16 HU in the descending aorta, with no significant difference in the mean value of the standard deviations between the four categories of BMI except for obese patients, who had a higher mean SD within the aorta. Interpolation artefacts were depicted in 22 patients, with a mean heart rate significantly lower than that of patients without interpolation artifacts, rated as mild in 11 patients and severe in 11 patients. The severity of interpolation artefacts

  6. Role of computed tomography (CT scan in staging of cervical carcinoma

    Directory of Open Access Journals (Sweden)

    T V Prasad

    2014-01-01

    Full Text Available Background & objectives: Staging of cervical carcinoma is done clinically using International Federation of Obstetrics and Gynecology (FIGO guidelines. It is based on physical examination findings and also includes results of biopsy, endoscopy and conventional radiological tests like chest radiograph, intravenous urography and barium enema. These conventional radiological investigations have largely been replaced by computed tomography (CT and magnetic resonance imaging (MRI at present. FIGO staging system does not consider CT and MRI mandatory; however, use of these modalities are encouraged. This prospective study was conducted to determine the role of CT in staging work up in women diagnosed with cervical carcinoma. Methods: Fifty three women diagnosed with cervical carcinoma were evaluated with contrast enhanced CT scan of abdomen and pelvis. CT scan images were especially evaluated to determine tumour size, invasion of parmetrium, pelvic walls, rectum, urinary bladder and ureters, pelvic or retroperitoneal lymphadenopathy and distant metastases. CT findings were associated with clinical findings and staging, including findings from cystoscopy and sigmoidoscopy. Results: There was a poor agreement between clinical and CT staging of cervical carcinoma. Primary tumour was demonstrated on CT in 36 (70% of 53 patients. CT underestimated the parametrial, vaginal and pelvic wall invasion when compared with physical examination. CT overestimated the urinary bladder and rectal invasion when compared with cysto-sigmoidoscopy, however, CT had 100 per cent negative predictive value (NPV to exclude bladder and rectal involvement. CT detection of lymph node enlargement and lung metastases influenced the management. Interpretation & conclusions: Our findings show that CT scan does not reliably correlate with clinical FIGO staging of cervical cancer. However, it can detect urinary obstruction as well as nodal or distant metastases and thus improves the

  7. A consideration of a measuring point of ventricular dilatation on CT scanning

    International Nuclear Information System (INIS)

    Kuno, Koichi; Miyake, Kazuo

    1980-01-01

    Ventricular dilatation has been judged by pneumo-ventricurography, pneumo-encepharography and carotid angiography (CAG), though all these procedures are very uncomfortable for patients. On the other hand, the CT scan is very easy as a follow-up study of ventricular dilatation for a weak patient. We carried out the CT scan (Hitachi CT-H 250 Scanner, NaI detector) and CAG on 84 cases. The ventricular dilatation was judged by the degree of outstretch of the strio-thalamic vein on an AP view of the phrebogram, classified into 3 types. For all three types classified by the phrebogram, we studied various measuring points of the ventricle on the CT scan. The portions measured on the CT scan were: (1) the frontal cerebro-ventricular index (F-CVI), (2) the bicaudate cerebro-ventricular index (Bicaud-CVI), and (3) the maximum Monro's cerebro-ventricular index (M-CVI), the width of the frontal horn, and the thickness of the ventricular body. The following results were obtained: (1) In measuring the ventricular size on the CT scan, the most interrelated point with the ventricular dilatation is the M-CVI - the ratio of the largest width of the body through the Monro foramen to the width of the brain. In this case, however, the width of the frontal horn and of the body should also be considered. (2) Voltage and electric current changed the EMI-number, but did not alter the measuring value. In this case, the width and the level should be kept constant. (3) The group with the marked ventricular dilatation has a larger value of the CT scan than its value of GAG. (4) The normal value of the M-CVI is 24 +- 3%, moreover, the width of the frontal horn is less than 10 mm, and the thickness of the ventricular body is less than 17 mm. (author)

  8. Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations

    International Nuclear Information System (INIS)

    Montes, C.; Hernandez, J.; Gomez-Caminero, F.; Garcia, S.; Martin, C.; Rosero, A.; Tamayo, P.

    2013-01-01

    Hybrid imaging, such as single photon emission computed tomography (SPECT)/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose. (author)

  9. Detection of active intraabdominal hemorrhage after blunt trauma: value of delayed CT scanning

    Energy Technology Data Exchange (ETDEWEB)

    Sivit, C.J. [Department of Radiology, Rainbow Babies and Children' s Hospital of the University Hospitals of Cleveland and Case Western Reserve School of Medicine, 11100 Euclid Avenue, Cleveland, OH (United States)

    2000-02-01

    Active hemorrhage is a rare finding at CT following blunt abdominal trauma. The time interval between IV contrast administration and scanning the abdomen may impact on the ability to visualize active hemorrhage at CT. We report a case of active hemorrhage associated with splenic injury that was identified only at delayed CT scanning. (orig.)

  10. Detection of active intraabdominal hemorrhage after blunt trauma: value of delayed CT scanning

    International Nuclear Information System (INIS)

    Sivit, C.J.

    2000-01-01

    Active hemorrhage is a rare finding at CT following blunt abdominal trauma. The time interval between IV contrast administration and scanning the abdomen may impact on the ability to visualize active hemorrhage at CT. We report a case of active hemorrhage associated with splenic injury that was identified only at delayed CT scanning. (orig.)

  11. Comparison between helical computed tomography angiography and intraoperative findings

    Directory of Open Access Journals (Sweden)

    Abijit Shetty

    2014-01-01

    Conclusions: Helical CT is important in delineating the arterial, venous, and ureteral anatomy and can show the important incidental findings. Left renal donors and males have more variations in their renal anatomy. Technically challenging laparoscopic nephrectomy on the multiple-vessel-side donor is possible with the aid of helical CT. The importance of the CT in evaluating donor renal anatomy for a technically challenging laparoscopic donor nephrectomy is commendable.

  12. Accuracy of cancellous bone volume fraction measured by micro-CT scanning

    DEFF Research Database (Denmark)

    Ding, Ming; Odgaard, A; Hvid, I

    1999-01-01

    Volume fraction, the single most important parameter in describing trabecular microstructure, can easily be calculated from three-dimensional reconstructions of micro-CT images. This study sought to quantify the accuracy of this measurement. One hundred and sixty human cancellous bone specimens...... which covered a large range of volume fraction (9.8-39.8%) were produced. The specimens were micro-CT scanned, and the volume fraction based on Archimedes' principle was determined as a reference. After scanning, all micro-CT data were segmented using individual thresholds determined by the scanner...

  13. A case of the CT scanning of a suicidal hanging brain

    International Nuclear Information System (INIS)

    Kawamata, Masaharu; Murooka, Hiroshi; Tanabe, Yasuhiko.

    1988-01-01

    A CT scanning of a case of hanging brain is reported. A 63-year-old man, who had been maintained with Aspirin (30 mg every morning) for cerebral infarction, attempted suicide by hanging, but failed. Several hours later, he was admitted because of consciousness disturbance and so was examined by means of CT scanning. Plain CT scanning showed symmetrical multiple intracerebral hemorrhages. Hemorrhages were found in the subcortical region of the bilateral temporal lobes and in the subependymal region near the foramen of Monro or in the choroidal plexus. We speculated that these hemorrhages may be caused by the congestion of the intracranial venous system caused by squeezing both internal jugular veins by hanging. Past angiograms (1981) for cerebral infarction revealed neither AVM nor angioma. (author)

  14. A review of patient dose and optimisation methods in adult and paediatric CT scanning

    International Nuclear Information System (INIS)

    Dougeni, E.; Faulkner, K.; Panayiotakis, G.

    2012-01-01

    Highlights: ► CT scanning frequency has grown with the development of new clinical applications. ► Up to 32-fold dose variation was observed for similar type of procedures. ► Scanning parameters should be optimised for patient size and clinical indication. ► Cancer risks knowledge amongst physicians of certain specialties was poor. ► A significant number of non-indicated CT scans could be eliminated. - Abstract: An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along

  15. CT scans of giant aneurysms in the vertebro-basilar artery

    International Nuclear Information System (INIS)

    Shishido, Toyofumi; Ohsugi, Tamotsu; Motozaki, Takahiko; Sakaki, Saburo; Matsuoka, Kenzo

    1980-01-01

    Clinical course and neurological and neuroradiological findings of giant aneurysms in the vertebro-basilar artery observed in two of our cases were discussed. The first case was a 66-year-old man. He complained of sensory disturbance over his left face and unstable gait for 2 years before admission. Neurological examinations on admission showed hypesthesia in the territory of the second branch of the left fifth cranial nerve, nystagmus, and a left cerebellar sign. No mental deterioration or pyramidal signs were noticed. Retrograde left brachial artery angiograms revealed a giant aneurysm with inferior pointing measuring 30 x 10 mm in diameter arising from the left superior cerebellar artery. Precontrast CT scans demonstrated a round, large, high-density area, cantaining a relatively low-density area within it, in the medioventral portion of the left cerebellum; a part of this high-density area was markedly enhanced in the postcontrast CT scan. No ventricular dilatations were noticed by CT scans. Direct surgery was abandoned due to the size and location of the aneurysm. No neurologically abnormal finding developed after discharge. The second case was a 61-year-old man. He complained of unstable gait for 2 years before admission. Neurological examinations on admission showed bilateral pyramidal sings (more pronounced on the left) and nystagmus. There were no cranial nerve palsy and no sensory disturbances. Precontrast CT scans showed a large, oval, high-density area in the medioventral portion of the right cerebellum, extending to the upper brainstem; a part of this high-density area was markedly enhanced in the postcontrast CT scans. Retrograde left brachial artery angiograms revealed that the fusiform aneurysm in the left vertebral, the basilar artery, and the dilated basilar artery ran 30 mm from the clivus, with a dorsal convex arch. (J.P.N.)

  16. Virtual endoscopy post-processing of helical CT data sets

    International Nuclear Information System (INIS)

    Dessl, A.; Giacomuzzi, S.M.; Springer, P.; Stoeger, A.; Pototschnig, C.; Voelklein, C.; Schreder, S.G.; Jaschke, W.

    1997-01-01

    Purpose: The purpose of this work was to test a newly developed, post-processing software for virtual CT endoscopic methods. Virtual endoscopic images were generated from helical CT data sets in the region of the shoulder joint (n=2), the tracheobronchial system (n=3), the nasal sinuses (n=2), the colon (n=2), and the common carotid artery (n=1). Software developed specifically for virtual endoscopy ('Navigator') was used which, after a previous threshold value selection, makes the reconstruction of internal body surfaces possible by an automatic segmentation process. We have evaluated the usage of the software, the reconstruction time for individual images and sequences of images as well as the quality of the reconstruction. All pathological findings of the virtual endoscopy were confirmed by surgery. Results: The post-processing program is easy to use and provides virtual endoscopic images within 50 seconds. Depending of the extent of the data set, virtual tracheobronchoscopy as a cine loop sequence required about 15 minutes. Thorugh use of the threshold value-dependent surface reconstruction the demands on the computer configuration are limited; however, this also created quality problems in image calculation as a consequence of the accompanying loss of data. Conclusions: The Navigator software enables the calculation of virtual endoscopic models with only moderate demands on the hardware. (orig.) [de

  17. Patient dose in CT fluoroscopy examinations

    International Nuclear Information System (INIS)

    Ito, Yusuke; Kobayashi, Masanao; Kataoka, Yumi; Ida, Yoshihiro; Kato, Ryoichi; Katada, Kazuhiro; Asada, Yasuki; Suzuki, Shoichi

    2008-01-01

    CT fluoroscopy(CTF) results in a high dose for the area under investigation in comparison with other types of examination. On the basis of data from April 2005 to March 2008, we measured the X-ray doses at the target site in CTF of the lungs, lumbar vertebrae, and pelvis as well as the X-ray dose to the female reproductive organs, and calculated the effective dose. The CT equipment used was an Aquilion 16. TLDs were inserted into an anthropomorphic phantom in positions corresponding to the target sites and the reproductive organs. Standard tube voltage and tube current were used as measurement conditions, and the scanning time used was the average value for each type of examination during the two years. Dose measurements were taken in the following order: scanography, helical scan, CTF, helical scan. X-ray element calibration was carried out through reciprocal comparison made between an ionization chamber dosimeter corrected according to government standards and the TLD for each tube voltage used for measurement. Dose estimation software was used to calculate the effective doses. During the two years there were 136 CTF examinations. These included 43 scans of the lungs, 13 of lumbar vertebrae, and 18 of the pelvis. The X-ray doses were 0.1 mGy at both the ovaries and the uterus for lung scans, 2 mGy at the ovaries and 1 mGy at the uterus for lumbar vertebrae scans, and 40 mGy at the ovaries and 20 mGy at the uterus for pelvic scans. The effective dose was highest for the lumbar vertebrae, followed by the lungs and finally the pelvis. (author)

  18. Anatomy of right superior septal artery demonstrated on the coronary CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Takeguchi, Takaya (Mitsui Memorial Hospital, Department of Diagnostic Radiology, Tokyo (Japan); Tokyo Medical and Dental University, Department of Diagnostic Radiology, Tokyo (Japan)); Ibukuro, Kenji; Fukuda, Hozumi; Tobe, Kimiko; Abe, Shoko (Mitsui Memorial Hospital, Department of Diagnostic Radiology, Tokyo (Japan)), Email: kj-ibkr@qd6.so-net.ne.jp

    2012-02-15

    Background. A coronary CT scan allows for non-invasive visualization of the anatomy of a coronary artery in three dimensions compared to the two dimensions afforded by conventional angiography. The septal artery, the main blood source of the interventricular septum, is usually derived from the left anterior descending artery; however, it is occasionally derived from the right coronary artery. Purpose. To analyze the prevalence, origin, diameter, and length of the right superior septal artery (RSSA) demonstrated on a coronary CT scan. Material and Methods. The right superior septal artery was retrospectively reviewed on the reconstructed axial scan images (0.5-mm thickness, 0.25-mm interval) in 1290 consecutive patients who underwent coronary CT scans. All patients were scanned on a 320-row CT scanner. The images were transferred to a workstation to trace the vessel to analyze the origin, diameter, and length. We also compared the length of the RSSA between patients with and without coronary artery stenosis. Results. The RSSA was identified in 51 (3.9%) of 1290 patients. The origin was the proximal portion of the right coronary artery (n = 40) or the right sinus of Valsalva (n 11). The artery co-existed with the conus artery in 15 (29%) of 51 patients. The length was 16-62 mm (mean 31.2 mm +- 10.5), and the diameter was 0.8-2.0 mm (mean 1.3 mm +- 0.2). Longer RSSAs tended to be demonstrated in the patients with coronary artery stenosis rather than with normal coronary arteries (P < 0.05). Conclusion. The right superior septal artery and its anatomical variant could be analyzed with a coronary CT scan. The ability to demonstrate this artery on the coronary CT scan was the same as with coronary angiography. The recognition of this vessel is useful for physicians managing with the diagnosis and treatment of the coronary artery disease

  19. X-CT imaging method for large objects using double offset scan mode

    International Nuclear Information System (INIS)

    Fu Jian; Lu Hongnian; Li Bing; Zhang Lei; Sun Jingjing

    2007-01-01

    In X-ray computed tomography (X-CT) inspection, rotate-only scanner is commonly used because this configuration offers the highest imaging speed and best utilization of X-ray dose. But it requires that the imaging region of the scanned object must fit within the X-ray beam. Another configuration, transverse-rotate scanner, has a bigger field of view, but it is much more time consuming. In this paper, a two-dimensional X-CT imaging method for large objects is proposed to overcome the existing disadvantages. The scan principle of this method has been described and the reconstruction algorithm has been deduced. The results of the computer simulation and the experiments show the validity of the new method. Analysis shows that the scan field of view of this method is 1.8 times larger than that of rotate-only X-CT. The scan speed of this method is also much quicker than transverse-rotate X-CT

  20. Computer graphic display of cardiac CT scans

    International Nuclear Information System (INIS)

    Palmer, R.; Carlsson, E.

    1982-01-01

    In order to improve spatial conception and quantitative assessment of the cardiac structures based on cardiac computed tomography, methods for computer graphic display were developed. Excised hearts and living dogs with myocardial infarctions were subjected to CT scanning. The data on the scanner tapes were processed to provide isodensity plots, linear section plots, time-weighted integrated isodensity plots as well as topographical density displays and three-dimensional spatial reconstructions of single and multi-layer scans. (orig.)

  1. Individualized radiation dose control in 256-slice CT coronary angiography (CTCA) in retrospective ECG-triggered helical scans: Using a measure of body size to adjust tube current selection

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing-Lei, E-mail: lijinglei80@126.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Huang, Mei-Ping, E-mail: huang_meiping@yahoo.com.cn [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Liang, Chang-Hong, E-mail: cjr.lchh@vip.163.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Zhao, Zhen-Jun, E-mail: junabc2006@hotmail.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Liu, Hui, E-mail: liuhuijiujiu@gmail.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Cui, Yan-Hai, E-mail: yanhai_cui@126.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Liu, Qi-Shun, E-mail: liuqishun@yeah.net [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Zhang, Jin-E., E-mail: zhjine@yahoo.com.cn [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Yang, Lin, E-mail: yanglin001517@163.com [Department of Radiology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, 106 Zhongshan Er Road, Guangzhou 510080 (China); Ivanc, Thomas B., E-mail: Thomas.ivanc@philips.com [CT Clinical Science, Philips Healthcare, Highland Heights, OH (United States); Yanof, Jeffrey H., E-mail: Jeffrey.yanof@philips.com [CT Clinical Science, Philips Healthcare, Highland Heights, OH (United States)

    2012-11-15

    Purpose: To reduce radiation dose for retrospective ECG-triggered helical 256-slice CTCA by determining an optimal body size index to prospectively adjust tube current. Methods: 102 consecutive patients with suspected CAD underwent retrospective ECG-triggered CTCA using 256-slice CT scanner. Six body size indexes including BMI, nipple level (NL) bust, thoracic anteroposterior diameter at NL, chest circumference (CC) at NL, left main and right coronary artery (RCA) origin level were measured and their correlation with noise was evaluated using linear regression. An equation was developed to use this index to adjust tube current. Additional 102 consecutive patients were scanned with the index-based mA s adjustment. A t-test for independent samples was used to compare radiation dose levels with and without the index-based mA s selection method. Results: Linear regression indicated that CC RCA had the best correlation with noise (R{sup 2} = 0.603). Effective radiation dose was reduced from 16.6 {+-} 0.9 to 9.8 {+-} 2.7 mSv (p < 0.01), i.e. 40.9% lower dose with the CC RCA-adapted tube current method. The image quality scores indicated no significant difference with and without the size-based mA s selection method. Conclusion: An accessible measure of body size, such as CC RCA, can be used to adapt tube current for individualized radiation dose control.

  2. Individualized radiation dose control in 256-slice CT coronary angiography (CTCA) in retrospective ECG-triggered helical scans: Using a measure of body size to adjust tube current selection

    International Nuclear Information System (INIS)

    Li, Jing-Lei; Huang, Mei-Ping; Liang, Chang-Hong; Zhao, Zhen-Jun; Liu, Hui; Cui, Yan-Hai; Liu, Qi-Shun; Zhang, Jin-E.; Yang, Lin; Ivanc, Thomas B.; Yanof, Jeffrey H.

    2012-01-01

    Purpose: To reduce radiation dose for retrospective ECG-triggered helical 256-slice CTCA by determining an optimal body size index to prospectively adjust tube current. Methods: 102 consecutive patients with suspected CAD underwent retrospective ECG-triggered CTCA using 256-slice CT scanner. Six body size indexes including BMI, nipple level (NL) bust, thoracic anteroposterior diameter at NL, chest circumference (CC) at NL, left main and right coronary artery (RCA) origin level were measured and their correlation with noise was evaluated using linear regression. An equation was developed to use this index to adjust tube current. Additional 102 consecutive patients were scanned with the index-based mA s adjustment. A t-test for independent samples was used to compare radiation dose levels with and without the index-based mA s selection method. Results: Linear regression indicated that CC RCA had the best correlation with noise (R 2 = 0.603). Effective radiation dose was reduced from 16.6 ± 0.9 to 9.8 ± 2.7 mSv (p < 0.01), i.e. 40.9% lower dose with the CC RCA-adapted tube current method. The image quality scores indicated no significant difference with and without the size-based mA s selection method. Conclusion: An accessible measure of body size, such as CC RCA, can be used to adapt tube current for individualized radiation dose control.

  3. Three-dimensional CT endoscopic images of the larynx. Clinical application of helical CT

    International Nuclear Information System (INIS)

    Yumoto, Eiji; Sanuki, Tetsuji; Yasuhara, Yoshifumi; Ochi, Takashi

    1998-01-01

    Twenty-seven patients with several laryngeal ailments underwent helical computed tomography (CT) on 37 occasions. Ten of these 27 patients suffered from unilateral vocal fold paralysis (UVFP). Three-dimensional (3D) images of the laryngeal lumen viewed from various angles were produced for all sets of CT volumetric data, except for three which contained excessive motion artifacts. The present paper examined whether 3D endoscopic images could offer useful diagnostic and therapeutic information about UVFP. The 3D endoscopic images viewed from the tracheal side and the hemilaryngeal images viewed from the opposite side could delineate the vocal folds, ventricular fold and ventricle three-dimensionally. Atrophy and hypotonic changes to the vocal fold and expansion of the ventricle on the affected side were clearly shown. The 3D endoscopic images accurately showed the phonosurgical effects on the laryngeal structures. The 3D endoscopic images could be produced even when the vocal folds could not be observed with conventional endoscopy due to their overadduction. Multiplanar reconstruction (MPR) images in the coronal plane were reconstructed at a right angle to the glottic axis when the whole larynx was deviated. In addition, coronal MPR images showed a better resolution among the different layers of the vocal fold soft tissue than X-ray tomography. In conclusion, 3D endoscopic images combined with coronal MPR images can provide useful diagnostic an therapeutic information about UVFP, although motion artifacts may occur. (author)

  4. The value of spiral CT scan on fracture of ankle joint and tarsal bones

    International Nuclear Information System (INIS)

    Li Zhaoli; Liang Jingyin; Pan Zhifeng

    2009-01-01

    Objective: To study the value of spiral CT scan on the fracture of ankle joint and tarsal bones. Methods: 43 cases with the fracture of ankle joint and tarsal bones were collected and analyzed. All the cases were examined by plain film radiography and spiral CT thin slice scan. Multi-planar reformation (MPR), surface shaded display (SSD) and other techniques of image post-processing were performed in 35 cases of them. Results: Spiral CT scan could demonstrate more fractures than plain film radiography in 28 cases(65.1%). There are 15 cases (34.9%) which are normal in plain film radiography but abnormal in Spiral CT scan. Spiral CT could demonstrate the different length, width, direction and number of linear low density shadow. SSD and MPR were performed again in the cases with avulsion fracture and fragmental fracture to demonstrate the fracture direction and the shape, size and location of fragments more clearly. Conclusion: Spiral CT thin slice scan with image post-processing techniques can play an important role in fracture of ankle joint and tarsal bones. (authors)

  5. Side-by-side reading of PET and CT scans in oncology: Which patients might profit from integrated PET/CT?

    International Nuclear Information System (INIS)

    Reinartz, Patrick; Wieres, Franz-Josef; Schneider, Wolfram; Schur, Alexander; Buell, Ulrich

    2004-01-01

    Most early publications on integrated positron emission tomography/computed tomography (PET/CT) devices have reported the new scanner generation to be superior to conventional PET. However, few of these studies have analysed the situation where, in addition to PET, a current CT scan is available for side-by-side viewing. This fact is important, because combined PET/CT or a software-based fusion of the two modalities may improve diagnosis only in cases where side-by-side reading of PET and CT data does not lead to a definitive diagnosis. The aim of this study was to analyse which patients will profit from integrated PET/CT in terms of lesion characterization. A total of 328 consecutively admitted patients referred for PET in whom a current CT scan was available were included in the study. The localization of all pathological PET lesions, as well as possible infiltration of adjacent anatomical structures, was assessed. Of 467 pathological lesions, 94.0% were correctly assessed with respect to localization and infiltration by either conventional PET alone (51.6%) or combined reading of PET and the already existing CT scans (42.4%). Hence, in only 6.0% of all lesions, affecting 6.7% of all patients, could evaluation have profited from integrated PET/CT. We conclude that side-by-side viewing of PET and CT scans is essential, as in 42.4% of all cases, combined viewing was important for a correct diagnosis in our series. In up to 6.7% of patients, integrated PET/CT might have given additional information, so that in nearly 50% of patients some form of combined viewing of PET and CT data is needed for accurate lesion characterization. (orig.)

  6. Strategies to reduce radiation dose in cardiac PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung Hsin; Wu, Nien-Yun [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wang, Shyh-Jen [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wu, Jay [Institute of Radiological science, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, No.91 Hsueh-Shih Road, Taichung 40402, Taiwan (China)

    2011-08-21

    Background: Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications. Materials: Image quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan. Results: Radiation dose in RGH technique was 22.2{+-}4.0 mSv. It was reduced to 10.95{+-}0.82 and 4.13{+-}0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53{+-}0.5 to 0.16{+-}0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols. Conclusion: The proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

  7. Progression of CT scan findings in Rett syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Hisaharu; Hirayama, Yoshito; Sakuragawa, Norio; Arima, Masataka (National Center of Neurology and Psychiatry, Kodaira, Tokyo (Japan))

    1989-07-01

    Progression of the lesions revealed by CT scan was observed in five girls with Rett syndrome. The most distinct and common finding was progressive dilatation of Sylvian fissures, frontal extracerebral space, interhemispheric fissure, and sulci mainly in frontal lobe. It may indicate progressive lesion in the frontal and the temporal lobes. In addition, dilatation of the anterior horns of the lateral ventricles and the third ventricle was noted in some cases. Brainstem and cerebellum were small at any age with some morphological development as the patients became elder. Neither malformations nor abnormalities in density were found in any case. It is concluded that the main lesion of Rett syndrome on CT scan is progressive and localized in the frontal and the temporal lobes. (author).

  8. CT scans in young people in Northern England: trends and patterns 1993-2002

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Mark S.; Salotti, Jane A.; Metcalf, Wenhua [Newcastle University, Sir James Spence Institute, Royal Victoria Infirmary, Institute of Health and Society, Newcastle upon Tyne (United Kingdom); McHugh, Kieran [Great Ormond Street Hospital for Children NHS Trust, London (United Kingdom); Kim, Kwang P. [Kyung Hee University, Department of Nuclear Engineering, Gyeongi-Do (Korea, Republic of); Craft, Alan W. [Newcastle University, Northern Institute of Cancer Research, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle upon Tyne (United Kingdom); Parker, Louise [Dalhousie University and Cancer Care Nova Scotia, Departments of Medicine and Paediatrics, Population Cancer Research Program, Halifax, NS (Canada); Ron, Elaine [National Cancer Institute, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Bethesda, MD (United States)

    2011-07-15

    Although CT can be greatly beneficial, its relatively high radiation doses have caused public health concerns. To assess patterns in CT usage among patients aged less than 22 years in Northern England during the period 1993-2002. Electronic data were obtained from radiology information systems of all nine National Health Service trusts in the region. A total of 38,681 scans had been performed in 20,483 patients aged less than 22 years. The number of CT examinations rose, with the steepest increase between 1997 and 2000. The number of patients scanned per year increased less dramatically, with 2.24/1,000 population aged less than 22 years having one scan or more in 1993 compared to 3.54/1,000 in 2002. This reflects an increase in the median number of scans per patient, which rose from 1 in 1993 to 2 by 1999. More than 70% of CT examinations were of the head, with the number of head examinations varying with time and patient age. The frequency of CT scans in this population more than doubled during the study period. This is partly, but not wholly, explained by an increase in the number of scans per patient. (orig.)

  9. Cushing's syndrome with an apparently normal CT scan

    International Nuclear Information System (INIS)

    Vlahos, L.; Strigaris, K.; Aliferopoulos, D.; Pontifex, G.

    1981-01-01

    A case of Cushing's syndrome is described in which the CT scan was considered as normal. The diagnosis was established with selective venography and blood sampling and was verified surgically. (orig.)

  10. The diagnostic value of PET/CT scanning in patients with cervical cancer

    DEFF Research Database (Denmark)

    Loft, Annika; Berthelsen, Anne Kiil; Roed, Henrik

    2007-01-01

    OBJECTIVE: To investigate the clinical value of PET/CT as a supplement to FIGO staging in patients with cervical cancer stage >or=1B. METHODS: This prospective study included 120 consecutive patients. After staging, a whole-body PET/CT scan was performed and these examinations were divided into two....../CT scanning for newly diagnosed cervical cancer FIGO stage >or=1B has a high sensitivity and specificity, and can be a valuable supplement to the FIGO staging procedure....

  11. Serial CT scans of cerebral hypoxia due to prolonged status epilepticus

    Energy Technology Data Exchange (ETDEWEB)

    Saiwai, Shigeo; Matsumura, Yasumasa; Tamaoka, Koichi; Fukuda, Teruo; Miyamoto, Takeshi [Kobe Central Municipal Hospital, Kobe (Japan)

    1983-04-01

    Serial computed tomography (CT) scans of 5 infants with status epilepticus were reviewed. Four out of the 5 infants fortunately had CT scans before status epilepticus because of a convulsion. There was a diffuse and mild low density in the hemisphere, with small ventricles and tight sulci (brain swelling) at 1 to 2 days after ictus. Thereafter, a diffuse low density became apparent except for the cerebellum, the brain stem, the thalamus, and the basal ganglia. Two to 4 weeks after ictus, a localized, mottled low density was demonstrated on the cerebral mantle and atrophic changes became progressively clear. In 3 cases, no abnormal enhancement was elicited on contrast CT scans performed between 5 to 16 days after status epilepticus. We discussed the possible pathophysiological aspects of the brain damage due to ''prolonged status epilepticus.''

  12. Analysis the findings of chest radiograph and CT scan in 217 acute thoracic trauma

    International Nuclear Information System (INIS)

    Huang Shaoying

    2005-01-01

    Objective: To evaluate chest radiograph and CT scan in assessing acute thoracic trauma. Methods: Retrospectively analyzed the findings of chest radiograph and CT scan in 217 cases of acute thoracic trauma and positive rate of each modality was compared. Results: The positive rate of rib and clavicle fracture was higher in chest radiograph than these in CT scan. But the positive rate of chest wall hematoma, mediastinum and subcutaneous emphysema, pneumothorax, hydropneumothorax, damage of lung parenchyma and traumatic pulmonary atelectasis was higher in CT scan than those in chest radiograph. Conclusion: The application of the combined imaging modalities improves assessing of acute thoracic trauma, because the imaging manifestation of the lesion is various. (authors)

  13. Ultrafast CT scanning of an oak log for internal defects

    Science.gov (United States)

    Francis G. Wagner; Fred W. Taylor; Douglas S. Ladd; Charles W. McMillin; Fredrick L. Roder

    1989-01-01

    Detecting internal defects in sawlogs and veneer logs with computerized tomographic (CT) scanning is possible, but has been impractical due to the long scanning time required. This research investigated a new scanner able to acquire 34 cross-sectional log scans per second. This scanning rate translates to a linear log feed rate of 85 feet (25.91 m) per minute at one...

  14. [Non-operation management of 12 cases with brain abscess demonstrated by CT scan].

    Science.gov (United States)

    Long, J

    1990-12-01

    This paper reported 12 cases with brain abscess demonstrated by CT scan. Using antibiotic management without surgical intervention, in 10 cases the curative effects were satisfactory. The paper indicated that CT scan was very useful in prompt and correct diagnosis of brain abscess and with sequential CT scan medical therapy was feasible. It is significant in treatment of brain abscess especially for the patients who have a poor general condition, have the brain abscess located in important functional area or have multiple abscesses so that the operation is difficult for them.

  15. Estimation of absorbed dose of radiosensitive organs and effective sose in patients underwent abdominopelvic spiral CT scan using impact CT patient dosimetry

    Directory of Open Access Journals (Sweden)

    Ayoub Amirnia

    2017-05-01

    Full Text Available Background: Due to the presence of radiosensitive organs in the abdominopelvic region and increasing the number of requests for CT scan examinations, concerns about increasing radiation doses in patients has been greatly elevated. Therefore, the goal of this study was to determine the absorbed dose of radiosensitive organs and the effective dose in patients underwent abdominopelvic CT scan using ImPACT CT patient dosimetry Calculator (version 1.0.4, Imaging Performance Assessment on Computed Tomography, www.impactscan.org. Methods: This prospective cross-sectional study was conducted in Imam Reza Hospital from November to February 2015 February 2015 in the Imam Reza Hospital, in Urmia, Iran. The demographic and dosimetric information of 100 patients who underwent abdominopelvic CT scan in a 6-slice CT scanner were obtained through the data collection forms. The demographic data of the patients included age, weight, gender, and BMI. The dosimetric parameters included pitch value, CT dose volume index (CTDIvol, dose-length product (DLP, tube voltage, tube current, exposure time, collimation size, scan length, and scan time. To determine the absorbed dose of radiosensitive organs and also the effective dose in patients, ImPACT CT patient dosimetry calculator was used. Results: The results of this study demonstrated that the mean and standard deviation (SD of patients' effective dose in abdominopelvic CT scan was 4.927±0.164 mSv. The bladder in both genders had the greatest mean organ dose, which was 64.71±17.15 mGy for men and 77.56±18.48 mGy for women (P<0.001. Conclusion: The effective dose values of this examination are in the same range as previous studies, as well as International Commission on Radiological Protection (ICRP recommendations. However, the radiation dose from CT scan has the largest contribution to the medical imaging. According to the ALARA principle, it is recommended that the scan parameters, especially mAs, should be

  16. Multislice Helical CT Angiography in Diagnostic of Intracranial and Extracranial Arterial Dissection

    International Nuclear Information System (INIS)

    Radzina, M.; Krumina, G.; Pupols, J.

    2007-01-01

    Arterial dissection is detachment of inner layer of the vessel wall. Head-neck trauma, congenital connectives tissue disorders like fibromuscular dysplasia, infectious diseases, hypertension, migraine, alcohol abuse and oral contraception are the typical causes. Urgent, complete, detailed verification is essential for successful treatment decision. Purpose. Aim of the study was to develop new appropriate CTA (angiography) protocols for patients with intracranial and extracranial arterial dissections using high speed multislice CT; to evaluate its clinical value in different locations and stages of disease, perspectives, advantages and disadvantages of new method. Materials and methods. 30 adult patients with suspected intra- or extracranial arterial blood vessels dissections were investigated in the clinical hospital 'Gailezers' using following algorithm: native CT; contrast CTA with post processing on the workstation. 80 ml iodine contrast media was administered intravenously, line speed 3-4 ml/sec, delay 10-15 seconds. For detection of maximum contrast intensity in the vessel the test contrast injection was performed before. Primary scan series were post processed in different kind of reconstructions - MPR (Multiplanar Reconstructions), MIP (Maximal Intensity Projection), VR (Volume Rendering), CR (Curved Reformat) and vessel analysis. Two different types of protocols were used - for intracranial and brachiocefalic arteries examinations. Results and Discussion. Following CTA symptoms of dissection were verified: 1) irregular vessel contour changes - narrowing, 'string' sign above dissection level; 2) tapered stenosis and/or distal occlusion; 3) double contour and/or double lumen sign; 4) fusiform aneurysmal dilatation. Clinical cases of different arterial dissection localization will be demonstrated during the presentation Advantages and disadvantages of CTA will be presented and disputed. Conclusions. CTA is non-invasive radiologic diagnostic method that yields

  17. Eighteen cases of small breast cancer: a comparative study of mammography, CT scan and pathology

    International Nuclear Information System (INIS)

    Wu Yaopan; Lin Haogao; Cai Peiqiang; Ouyang Yi; Zhang Weizhang; Lu Bingui

    2003-01-01

    Objective: To improve the early diagnosis of breast cancer through a study of the mammography and CT findings of small breast cancer. Methods: The mammography and CT findings of 18 cases of small breast cancer (φ≤2.0 cm in diameter) were studied and compared with pathological results. Results: The diagnostic accuracy of CT and mammography was 83% and 61%, respectively. There was a statistical difference between both modalities (P<0.05), CT scan was superior to mammography. However, there was no difference between them when assessing the lesion arising in F-type breast. In detecting breast fine cluster of calcification, the sensitivity of mammography was better than CT scan. Conclusion: The patient suspected of small breast cancer should take mammography as the first evaluation. CT scan is reserved for the further investigation. The mammography combined with CT scan can improve the early diagnostic rate of breast cancer

  18. Analysis of cranial CT-scan findings in cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Wada, F.; Andoh, T.; Une, K.; Takamatsu, T. (Kitakyushu Municipal Sogo-Ryoiku Center (Japan))

    1981-06-01

    CT-scan findings of 87 cerebral palsied children were studied. They consist of 23 cases of spastic quadriplegia, 9 cases of diplegia, 12 cases of paraplegia, 24 cases of athetosis and mixed type, and 19 cases of hemiplegia. In the former four types, ventricular dilatation and cortical atrophy were measured and abnormal changes in cerebral substance and cerebellar atrophy were observed. Spastic quadriplegia showed most intense changes in every aspect of the abnormalities, while paraplegia had almost normal appearance. Athetosis and mixed type had moderate changes. Hemiplegia always showed asymmetrical view on CT-scan, dilatation of lateral ventricle or atrophy of hemisphere in contralateral side being observed.

  19. Analysis of cranial CT-scan findings in cerebral palsy

    International Nuclear Information System (INIS)

    Wada, Fumio; Andoh, Tadashi; Une, Koji; Takamatsu, Tsurukichi

    1981-01-01

    CT-scan findings of 87 cerebral palsied children were studied. They consist of 23 cases of spastic quadriplegia, 9 cases of diplegia, 12 cases of paraplegia, 24 cases of athetosis and mixed type, and 19 cases of hemiplegia. In the former four types, ventricular dilatation and cortical atrophy were measured and abnormal changes in cerebral substance and cerebellar atrophy were observed. Spastic quadriplegia showed most intense changes in every aspect of the abnormalities, while paraplegia had almost normal appearance. Athetosis and mixed type had moderate changes. Hemiplegia always showed asymmetrical view on CT-scan, dilatation of lateral ventricle or atrophy of hemisphere in contralateral side being observed. (author)

  20. Introduction of the Canadian CT Head Rule Reduces CT Scan Use ...

    African Journals Online (AJOL)

    amnesia or witnessed disorientation in a patient with a GCS score of 13–15 who has suffered a traumatic event, the evaluation of minor head injury using. Computerized Axial Tomography Scan of the Head. (CT-head) has remained controversial.(1,3). CT–head is expensive, time consuming, strenuous to human resource ...

  1. Study on the brain CT scan of SLE patients

    Energy Technology Data Exchange (ETDEWEB)

    Nagaoka, S; Narita, M; Katoh, K; Matsunaga, K; Ishigatsubo, Y [Yokohama City Univ. (Japan). Faculty of Medicine

    1982-03-01

    Cranial CT scanning revealed abnormality in 12 of 25 patients with SLE (48%). Ventricular sulcal enlargement was found mostly in younger patients between 16 and 36 years, an average of 25 years. Abnormality in electroencephalogram, principally paroxysmal abnormality, was found in 8 of 13 cases (62%) of normal CT findings. Non-paroxysmal slow-wave abnormality was observed in 9 of 12 abnormal CT cases. Of 13 patients with CNS symptoms, 8 had abnormal CT findings, and 5 had only mental disorder with normal CT findings. In 12 patients without neuropsychiatric involvement, 4 (33%) had abnormal CT findings. The rate of abnormal CT findings was increased in the patients receiving a high dosage of a steroid agent. Five of 6 patients who showed ventricular sulcal enlargement had been given prednisolone in a dosage of 35 mg or more per day.

  2. Significance and problems of the dynamic CT scan for the diagnosis and treatment of cerebral infarctions

    International Nuclear Information System (INIS)

    Morita, Akio; Teraoka, Akira

    1985-01-01

    Dynamic CT scan is a very useful method for the diagnosis of cerebral infarctions and other ischemic disorders. We have used this method for 1) the ultra-early stage diagnosis of major infarctions, 2) the detection of the recanalization and the disruption of the blood-brain barrier, and 3) the detection of latent ischemic lesions. In this report we discussed the clinical cases and the usual use of this dynamic CT scan. We used a GE CT/T8800 scanner for dynamic CT scanning. Manual bolus-contrast-medium injection was done simultaneously with the first scanning, and 6 sequential scannings (scan time: 4.8 s; scan interval: 1.4 s) were done on the same slice level. Especially in major infarctions (e.g., MCA occlusion), OM 40 was the most preferred slice. In cases of ultra-early stage infarctions (i.e., no abnormal lesions in non-enhanced CT), we used this dynamic CT scan immediately after the non-enhanced CT; we could thus obtain information on the ischemic lesions and the ischemic degree. After that we repeated this examination on Days 3, 7, and 14 for the evaluation of the recanalization and blood-brain-barrier disruption. In the cases of TIA and impending or progressing strokes, dynamic CT scan could disclose latent ischemic lesions; in there instances, we treated the patients with intensive to prevent the prognosis from worsening. These benefits and also some problems were discussed. (author)

  3. Standardized CT examination of the multitraumatized patient

    Energy Technology Data Exchange (ETDEWEB)

    Leidner, B. [Department of Diagnostic Radiology, Oskarshamn Hospital (Sweden)]|[Department of Diagnostic Radiology, Huddinge University Hospital (Sweden); Adiels, M. [Department of Diagnostic Radiology, Oskarshamn Hospital (Sweden); Aspelin, P. [Department of Diagnostic Radiology, Huddinge University Hospital (Sweden); Gullstrand, P.; Wallen, S. [Department of Surgery, Oskarshamn Hospital (Sweden)

    1998-12-01

    The aim of this study was to develop a standardized non-helical-CT protocol including head, body and proximal extremities in order to achieve a good time efficiency and diagnostic accuracy in the initial radiological evaluation of the multitraumatized patient. A total of 111 circulatory stable blunt trauma patients, brought in to a trauma level II-III hospital, were examined according to a standardized CT protocol. After examining the head with contiguous 10-mm slices without IV contrast medium injection, the trunk was examined with 10-mm slices every 30 mm through thorax-abdomen-pelvis with IV contrast medium enhancement (occasionally modified). All data in the medical reports were collected and used as ``end-point``, and the outcome of the CT examination was compared with this final diagnosis. Mean examination time was 20 min (range 12-32 min). In total, 55 head injuries, 89 thoracic injuries, 27 abdominal/pelvic injuries and 62 fractures were found. Computed tomography correctly identified the injuries, except one brain stem injury, one contusion/rupture of the heart, one hepatic injury, two intestinal injuries, eight vertebral injuries and one joint dislocation. A standardized non-helical-CT examination of the head and body may be achieved in 20 min. Its diagnostic accuracy was high, except for vertebral column injuries, which is why we recommend it as the method of choice for initial radiological examination of multitraumatized patients. When available, helical scanning would improve both examination speed and accuracy. (orig.) With 6 figs., 40 refs.

  4. Utility of CT scan for the diagnosis of chest wall tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, A.; Le Breton, C.; Tassart, M.; Korzec, J.; Bigot, J.M.; Carette, M.F. [Department of Radiology, Tenon Hospital, Paris (France)

    1999-10-01

    The objective of this study was to determine the utility of CT scan findings for the diagnosis of chest wall tuberculosis, excluding the spine. We reviewed 15 patients (13 Africans and 2 Indians) with chest wall tuberculosis, retrospectively. The radiologic examination consisted of a plain X-ray and a CT scan of the chest for each patient. The site of disease was the rib in 13 patients or the body of the sternum in 2 patients. One rib was involved in 11 patients, 2 contiguous ribs (one site) in 2 patients, and bilateral disease (two sites) was observed in the remaining patient. The 14 rib sites involved the posterior arc or costovertebral joint in 11 cases, the anterior arc in 2 cases, and the anterior and middle arc in 1 case. The CT scan findings were an abscess (n = 14) or a soft tissue mass (n = 2), osteolytic lesions (n = 13), periosteal reaction (n = 10), and sequestrum (n = 14). Bone sclerosis was observed only in 3 cases of rib involvement. The association of a soft tissue abscess, an osteolytic lesion, and sequestrum, especially in immigrants to France, suggests chest wall tuberculosis on CT scan. (orig.) With 5 figs., 2 tabs., 11 refs.

  5. CT scanning in stroke patients: meeting the challenge in the remote and rural district general hospital.

    Science.gov (United States)

    Todd, A W; Anderson, E M

    2009-05-01

    National audit data allow crude comparison between centres and indicate that most Scottish hospitals fail to meet current guidelines for CT scanning of the brain in stroke patients. This study identifies some of the reasons for delay in performing CT scans in a largely rural population. This audit study assesses the delays from onset of symptoms, time of admission and request received to CT scan in stroke patients for three different in-patient groups as well as those managed in the community. The reasons for delay in CT scanning varied between different patient groups but for one group of in-patients, changes in booking procedure and introduction of a second CT scanner increased the proportion scanned within 48 hours of request from 65% to 96%. Further developments including the introduction of Saturday and Sunday routine CT scanning, radiologist reporting from home and additional CT scanners placed in remote hospitals may be expected to improve these figures further. Target times of three hours from onset of symptoms to scan to allow thrombolysis may however be impossible to meet for all stroke patients in rural areas.

  6. Serial CT scans of cerebral hypoxia due to prolonged status epilepticus

    Energy Technology Data Exchange (ETDEWEB)

    Saiwai, Shigeo; Matsumura, Yasumasa; Tamaoka, Koichi; Fukuda, Teruo; Miyamoto, Takeshi (Kobe Central Municipal Hospital, Kobe (Japan))

    1983-04-01

    Serial computed tomography (CT) scans of 5 infants with status epilepticus were reviewed. Four out of the 5 infants fortunately had CT scans before status epilepticus because of a convulsion. There was a diffuse and mild low density in the hemisphere, with small ventricles and tight sulci (brain swelling) at 1 to 2 days after ictus. Thereafter, a diffuse low density became apparent except for the cerebellum, the brain stem, the thalamus, and the basal ganglia. Two to 4 weeks after ictus, a localized, mottled low density was demonstrated on the cerebral mantle and atrophic changes became progressively clear. In 3 cases, no abnormal enhancement was elicited on contrast CT scans performed between 5 to 16 days after status epilepticus. We discussed the possible pathophysiological aspects of the brain damage due to ''prolonged status epilepticus.''

  7. Feasibility of F-18-FDG PET/CT scan in abdominopelvic regions

    International Nuclear Information System (INIS)

    Suga, Kazuyoshi

    2008-01-01

    F-18-2-Fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT scan, which simultaneously provides metabolic function and morphology on the same tomographic section, is being the key imaging modality for diagnosis and treatment strategy of makignancies in various organs. FDG PET/CT scanning of the whole body beneficially allows the assessment of primary tumor and regional lymph nodes, and distant metastases and co-existed benign/other malignant lesions, as ''one stop shopping'' fashion. This technique contributes to the selection of the optimal treatment in individual patients, and also can predict histopathologic response to treatment and postoperative/post chemo-radiation therapeutic prognosis. In this paper, we describe the fundamental knowledge required for accurate interpretation of FDG PET/CT scan, and review the utility of this technique for diagnosis and treatment strategy of makignancies in abdominal and pelvic regions. (author)

  8. Serial CT scans of cerebral hypoxia due to prolonged status epilepticus

    International Nuclear Information System (INIS)

    Saiwai, Shigeo; Matsumura, Yasumasa; Tamaoka, Koichi; Fukuda, Teruo; Miyamoto, Takeshi

    1983-01-01

    Serial computed tomography (CT) scans of 5 infants with status epilepticus were reviewed. Four out of the 5 infants fortunately had CT scans before status epilepticus because of a convulsion. There was a diffuse and mild low density in the hemisphere, with small ventricles and tight sulci (brain swelling) at 1 to 2 days after ictus. Thereafter, a diffuse low density became apparent except for the cerebellum, the brain stem, the thalamus, and the basal ganglia. Two to 4 weeks after ictus, a localized, mottled low density was demonstrated on the cerebral mantle and atrophic changes became progressively clear. In 3 cases, no abnormal enhancement was elicited on contrast CT scans performed between 5 to 16 days after status epilepticus. We discussed the possible pathophysiological aspects of the brain damage due to ''prolonged status epilepticus.'' (author)

  9. Focal hepatic steatosis: ultrasound and CT scan features may mimick carcinoma of the liver

    International Nuclear Information System (INIS)

    Monnin, J.L.; Blanc, F.; Guiry, P.; Bruel, J.M.; Monnin, E.; Ciurana, A.J.

    1988-01-01

    Ultrasound and CT scan features of focal hepatic steatosis (FHS) may closely resemble those of primary or secondary malignant hepatic tumors. Three cases of FHS in chronic alcoholics are reported. In two cases, the area of steatosis was hyperechogenic upon ultrasonography. In all three patients, CT scan demonstrated a hypodense image, with poor enhancement following opacification and no mass effect. Diagnosis of FHS was ascertained upon hepatic biopsy under CT scan guidance in all three patients [fr

  10. Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration.

    Science.gov (United States)

    Wolthaus, J W H; Sonke, J J; van Herk, M; Damen, E M F

    2008-09-01

    lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods noise of individual 4D CT scan frames. We implemented an accurate method to estimate the motion of structures in a 4D CT scan. Subsequently, a

  11. Anatomy of right superior septal artery demonstrated on the coronary CT scan

    International Nuclear Information System (INIS)

    Takeguchi, Takaya; Ibukuro, Kenji; Fukuda, Hozumi; Tobe, Kimiko; Abe, Shoko

    2012-01-01

    Background. A coronary CT scan allows for non-invasive visualization of the anatomy of a coronary artery in three dimensions compared to the two dimensions afforded by conventional angiography. The septal artery, the main blood source of the interventricular septum, is usually derived from the left anterior descending artery; however, it is occasionally derived from the right coronary artery. Purpose. To analyze the prevalence, origin, diameter, and length of the right superior septal artery (RSSA) demonstrated on a coronary CT scan. Material and Methods. The right superior septal artery was retrospectively reviewed on the reconstructed axial scan images (0.5-mm thickness, 0.25-mm interval) in 1290 consecutive patients who underwent coronary CT scans. All patients were scanned on a 320-row CT scanner. The images were transferred to a workstation to trace the vessel to analyze the origin, diameter, and length. We also compared the length of the RSSA between patients with and without coronary artery stenosis. Results. The RSSA was identified in 51 (3.9%) of 1290 patients. The origin was the proximal portion of the right coronary artery (n = 40) or the right sinus of Valsalva (n 11). The artery co-existed with the conus artery in 15 (29%) of 51 patients. The length was 16-62 mm (mean 31.2 mm ± 10.5), and the diameter was 0.8-2.0 mm (mean 1.3 mm ± 0.2). Longer RSSAs tended to be demonstrated in the patients with coronary artery stenosis rather than with normal coronary arteries (P < 0.05). Conclusion. The right superior septal artery and its anatomical variant could be analyzed with a coronary CT scan. The ability to demonstrate this artery on the coronary CT scan was the same as with coronary angiography. The recognition of this vessel is useful for physicians managing with the diagnosis and treatment of the coronary artery disease

  12. Quantitative measurement of ventricular dilatation on CT scan

    International Nuclear Information System (INIS)

    Okita, Naoshi; Mochizuki, Hiroshi; Takase, Sadao

    1985-01-01

    Cerebral atrophy might be judged from the ventricular dilatation with some indices, calculated from various ventricular width. But, there is no general agreement on what index is the most reliable. In this paper, we attempted to establish the index, easy to measure and most reliable. Our method is as follow. 1) We carried out the CT scan (EMI 1010) on 89 neurologically intact patients. Scans were parallel to orbito-meatal line (OML), and were 10 mm in thickness. On CT scan films, various width, area of anterior horns and area of bodies of lateral ventricles were measured. Measurement about the anterior horns of lateral ventricles were carried out on image the most clearly showed the foramen of Monro. And measurements about the bodies of lateral ventricles were on image, 20 mm above the image of anterior horn. Correlations of various width and areas were calculated. Then we proposed new indices with high correlations (over 0.9) with ventricular area; Anterior horn CVI (Cerebro-Ventricular Index) and Body CVI. 2) Patients with myotonic dystrophy show cerebral atrophy. We carried out the CT scan (GECT/T 8800) on 17 myotonic dystrophy patients and 30 controls. Between the two groups, age and sex were almost matched. In the two groups, we calculated our new indices as well as various indices which have been reported; Huckman number, Bifrontal CVI, Bicaudal CVI, Anterior horn index, Hirajima's index, and Cella-media index. The data were analyzed statistically. The ventricular dilatation of myotonic dystrophy patients is more definite with Anterior horn CVI, Bicaudal CVI and Body CVI (p<0.01). These indices have higher correlations with the ventricular area (about 0.9). (J.P.N.)

  13. A case of pineal teratoma with intraventricular free fat on CT scan

    International Nuclear Information System (INIS)

    Uede, Teiji; Takaya, Satoru; Shinya, Toshiyuki; Tanabe, Sumiyoshi; Hashi, Kazuo; Sohma, Tsutomu.

    1986-01-01

    Detection of an intraventricular or intratumoral fat-fluid level on the plain craniograms has been known as a characteristic sign indicating the presence of intracranial teratomatous tumors. On CT scans, however, only thirteen cases have been previously reported to be found an intraventricular and/or subarachnoid free fat associated with spontaneous ruptures of these tumors. We reported a case of pineal teratoma with intraventricular free-fat seen on CT scans. A nine-year-old male with precocious puberty was admitted to our hospital complaining a moderate nonpulsatile headache. Neurological examinations were normal without signs of meningeal irritation. The serum and CSF titer of HCG were raised markedly. The laboratory data of the CSF were normal and there were no pathological cells in the CSF. The CT scans revealed a large heterogeneous mass containing multiple areas of negative density in the pineal region. There were negative density droplets in the bilateral frontal horn on the same CT scans indicating a presence of free fats. At surgery, an yellowish oily material was drained from the tumor, but there was no sign of meningitis over the cortical surface of the occipital lobe. An intraventricular free fat on CT scan have been reported in fourteen cases including ours following the first case described by Fawcitt in 1976. Although most of the cases presented headache, only two cases was diagnosed clinically as chemical meningitis. Pathological changes indicating granulomatous meningitis, however, were noted in five cases, all of them presenting seizure attacks. (author)

  14. Colon distension and scan protocol for CT-colonography: an overview

    NARCIS (Netherlands)

    Boellaard, Thierry N.; de Haan, Margriet C.; Venema, Henk W.; Stoker, Jaap

    2013-01-01

    This article reviews two important aspects of CT-colonography, namely colonic distension and scan parameters. Adequate distension should be obtained to visualize the complete colonic lumen and optimal scan parameters should be used to prevent unnecessary radiation burden. For optimal distension,

  15. Brain tumors and CT scan in infants and children, (1). The impact on pediatric neuroradiology

    Energy Technology Data Exchange (ETDEWEB)

    Ohi, S; Velasco, J M [Northwestern Univ., Chicago, IL (USA). Medical School

    1980-10-01

    The dramatic change in the neuroradiological procedures have been noted after CT scan was introduced in the last several years. Remarkable decreasing numbers of angiographic, pneumoencephalographic and other invasive neuroradiologic studies as well as nuclear brain scan were also found in the pediatric neuroradiology. The authors analyzed the total numbers of these studies performed in the last several years in pediatric neurological/neurosurgical practice in the light of the impact of CT scan especially in the diagnostic procedures and treatments of brain tumor in children. Although the number of these procedures decreased up to 49% in plain skull X-ray, 54% in cerebral angiography, 70% in pneumoencephalography/ventriculography and 79% in nuclear brain scan after CT scan was installed in our results, it is extremely important to renew understanding of those characteristics in each special procedures. Cerebral angiography as well as pneumoencephalography may give the surgeon more precise ideas of the anatomical relationship between the lesion and other normal structures, especially in the posterior fossa tumor in which CT scan occassionally demonstrates only a gross finding. A case with false negative result and another case with a complicated anatomical structure in CT scan were presented. The significance of cerebral angiography and other invasive studies in the diagnosis and follow up of brain tumor in CT scan were discussed.

  16. Performance characterization of megavoltage computed tomography imaging on a helical tomotherapy unit

    International Nuclear Information System (INIS)

    Meeks, Sanford L.; Harmon, Joseph F. Jr.; Langen, Katja M.; Willoughby, Twyla R.; Wagner, Thomas H.; Kupelian, Patrick A.

    2005-01-01

    Helical tomotherapy is an innovative means of delivering IGRT and IMRT using a device that combines features of a linear accelerator and a helical computed tomography (CT) scanner. The HI-ART II can generate CT images from the same megavoltage x-ray beam it uses for treatment. These megavoltage CT (MVCT) images offer verification of the patient position prior to and potentially during radiation therapy. Since the unit uses the actual treatment beam as the x-ray source for image acquisition, no surrogate telemetry systems are required to register image space to treatment space. The disadvantage to using the treatment beam for imaging, however, is that the physics of radiation interactions in the megavoltage energy range may force compromises between the dose delivered and the image quality in comparison to diagnostic CT scanners. The performance of the system is therefore characterized in terms of objective measures of noise, uniformity, contrast, and spatial resolution as a function of the dose delivered by the MVCT beam. The uniformity and spatial resolutions of MVCT images generated by the HI-ART II are comparable to that of diagnostic CT images. Furthermore, the MVCT scan contrast is linear with respect to the electron density of material imaged. MVCT images do not have the same performance characteristics as state-of-the art diagnostic CT scanners when one objectively examines noise and low-contrast resolution. These inferior results may be explained, at least partially, by the low doses delivered by our unit; the dose is 1.1 cGy in a 20 cm diameter cylindrical phantom. In spite of the poorer low-contrast resolution, these relatively low-dose MVCT scans provide sufficient contrast to delineate many soft-tissue structures. Hence, these images are useful not only for verifying the patient's position at the time of therapy, but they are also sufficient for delineating many anatomic structures. In conjunction with the ability to recalculate radiotherapy doses on

  17. Comparison of absorbed dose of two protocols of tomographic scanning in PET/CT exams

    International Nuclear Information System (INIS)

    Paiva, F.G.

    2017-01-01

    Positron Emission Tomography (PET) associated with Computed Tomography (CT) allows the fusion of functional and anatomical images. When compared to other diagnostic techniques, PET-CT subjects patients to higher levels of radiation, because two modalities are used in a single exam. In this study, the doses absorbed in 19 patient organs from the tomographic scan were evaluated. Radiochromic films were correctly positioned in the Alderson anthropomorphic simulator, male version. For evaluation, two whole body scan protocols were compared. For evaluation, two whole body scan protocols were compared. An increase of up to 600% in the absorbed dose in the pituitary was observed when the protocols were compared, with the lowest observed increase of approximately 160% for the liver. It is concluded that the dose from CT in patients submitted to PET-CT scanning is higher in the protocol used for diagnosis. Considering the high cost of PET-CT exam, in many cases it is preferable that the CT examination is of diagnostic quality, and not only for anatomical mapping, an argument based on the Principle of Justification

  18. Mediastinal lymph node enlargement on CT scans in idiopathic pulmonary fibrosis

    International Nuclear Information System (INIS)

    Ahn, Joong Mo; Im, Jung Gi; Yu, Kyu In; Kim, Hyeong Seog; Kim, Dae Young; Yu, Pil Mun

    1992-01-01

    The increase in size of lymph node on CT scan is the single most important finding of lymphadenopathy. The purpose of this study was to evaluate the size of mediastinal lymph nodes in patients with idiopathic pulmonary fibrosis with no evidence of malignancy or current infection. CT scans of 70 patients (16 with conventional CT and 54 with high-resolution CT) were assessed for lymph node size and location. The duration of symptoms, and the extent and pattern of the parenchymal lung disease on CT scans were correlated with lymph node enlargement. In 54 of 70 patients, more than one lymph nodes were large than 1-1.5 cm. The prevalence of node enlargement increased significant with a longer duration of symptom (p=0.001), large extent of the disease (p=0.043), and with a greater proportion of honeycomb pattern (p=0.033). Right paratracheal, subcarinal, right tracheobronchial, and paraesophageal nodes were the most common sites of node enlargement. In conclusion, mediastinal lymph node enlargement is common in patients with idiopathic pulmonary fibrosis and is more frequently seen in patients with a longer duration of clinical symptoms, greater extent of the disease, and with a larger proportion of honeycomb pattern

  19. Mediastinal lymph node enlargement on CT scans in idiopathic pulmonary fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Joong Mo; Im, Jung Gi; Yu, Kyu In; Kim, Hyeong Seog [Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Dae Young [Chung Buk National University College of Medicine, Chungju (Korea, Republic of); Yu, Pil Mun [Dankuk University College of Medicine, Seoul (Korea, Republic of)

    1992-09-15

    The increase in size of lymph node on CT scan is the single most important finding of lymphadenopathy. The purpose of this study was to evaluate the size of mediastinal lymph nodes in patients with idiopathic pulmonary fibrosis with no evidence of malignancy or current infection. CT scans of 70 patients (16 with conventional CT and 54 with high-resolution CT) were assessed for lymph node size and location. The duration of symptoms, and the extent and pattern of the parenchymal lung disease on CT scans were correlated with lymph node enlargement. In 54 of 70 patients, more than one lymph nodes were large than 1-1.5 cm. The prevalence of node enlargement increased significant with a longer duration of symptom (p=0.001), large extent of the disease (p=0.043), and with a greater proportion of honeycomb pattern (p=0.033). Right paratracheal, subcarinal, right tracheobronchial, and paraesophageal nodes were the most common sites of node enlargement. In conclusion, mediastinal lymph node enlargement is common in patients with idiopathic pulmonary fibrosis and is more frequently seen in patients with a longer duration of clinical symptoms, greater extent of the disease, and with a larger proportion of honeycomb pattern.

  20. Increased inspiratory pressure for reduction of atelectasis in children anesthetized for CT scan

    International Nuclear Information System (INIS)

    Sargent, Michael A.; Jamieson, Douglas H.; McEachern, Anita M.; Blackstock, Derek

    2002-01-01

    Background: Atelectasis is more frequent and more severe in children anesthetized for CT scan than it is in children sedated for CT scan.Objective: To determine the effect of increased inspiratory pressure on atelectasis during chest CT in anesthetized children. Materials and methods: Atelectasis on chest CT was assessed by two observers in three groups of patients. Group A comprised 13 children (26 lungs) anesthetized at inspiratory pressures up to and including 25 cm H 2 O. Group B included 11 children anesthetized at inspiratory pressures ≥30 cm H 2 O. Group C included 8 children under deep sedation. Results: Atelectasis was significantly more severe in group A than in groups B and C. There was no significant difference between groups B and C. Conclusion: An inspiratory pressure of 30 cm H 2 O is recommended for children anesthetized for CT scan of the chest. (orig.)

  1. Introduction of helical computed tomography affects patient selection for V/Q lung scan

    International Nuclear Information System (INIS)

    Zettinig, G.; Baudrexel, S.; Leitha, Th.

    2002-01-01

    Aim: Retrospective analysis for determination of the effect of helical computed tomography (HCT) on utilization of V/Q lung scanning to diagnose pulmonary embolism (PE) in a large general hospital. Methods: A total number of 2676 V/Q scans of in- and out-patients referred to our department between March 1992 and December 1998 and between April 1997 and December 1998 were analyzed by an identical group of nuclear physicians. Results: Neither the total number of annually performed V/Q scans (446 ± 135) nor the mean age of patients (56 years ± 17) changed significantly since the introduction of HCT. However, the referral pattern was different. The percentage of patients with high and intermediate probability for PE decreased significantly from 15.2% to 9.4% (p <0.01) and from 10.2% to 7.3% (p <0.05), respectively. Low probability scans significantly increased from 37.8% to 42.7% (p <0.05). The percentage of normal scans did not change significantly, however, there was a highly significant increase summarizing patients with normal and low probability scans (74.6% to 83.3%; p <0.01). Conclusion: The introduction of HCT affected the selection of patients referred for V/Q lung scanning since V/Q scanning was primarily used to exclude rather to confirm PE. (orig.)

  2. Aortic valve calcification - a commonly observed but frequently ignored finding during CT scanning of the chest.

    Science.gov (United States)

    Raju, Prashanth; Sallomi, David; George, Bindu; Patel, Hitesh; Patel, Nikhil; Lloyd, Guy

    2012-06-01

    To describe the frequency and severity of Aortic valve calcification (AVC) in an unselected cohort of patients undergoing chest CT scanning and to assess the frequency with which AVC was being reported in the radiology reports. Consecutive CT scan images of the chest and the radiological reports (December 2009 to May 2010) were reviewed at the district general hospital (DGH). AVC on CT scan was visually graded on a scale ranging from 0 to IV (0 = no calcification, IV = severe calcification). Total of 416 (232 male; 184 female) CT chest scans [Contrast enhanced 302 (72%), unenhanced 114 (28%)] were reviewed. Mean age was 70.55 ± 11.48 years. AVC in CT scans was identified in 95 of the 416 patients (22.83%). AVC classification was as follows: Grade I: 60 (63.15%), Grade II: 22 (23.15%), Grade III: 9 (9.47%), Grade IV: 4 (4.21%). Only one CT report mentioned AVC. Only 31 of 95 AVC had Transthoracic echocardiogram (TTE). The interval time between CT scan and TTE was variable.   Aortic valve calcification in CT chest scans is a common finding and studies have shown that it is strongly related to the presence and severity of aortic valve disease. As CT scans are considered as a valuable additional screening tool for detection of aortic stenosis, AVC should always be commented upon in the radiology reports. Furthermore, patients with at least Grade III and IV AVC should be sent for TTE. © 2012 Blackwell Publishing Ltd.

  3. Suitability of helical multislice acquisition technique for routine unenhanced brain CT: an image quality study using a 16-row detector configuration

    Energy Technology Data Exchange (ETDEWEB)

    Hernalsteen, Danielle; Cosnard, Guy; Grandin, Cecile; Duprez, Thierry [Universite Catholique de Louvain, Cliniques Universitaires Saint-Luc, Department of Radiology and Medical Imaging, Brussels (Belgium); Robert, Annie [Public Health School, Universite Catholique de Louvain, Department of Epidemiologics and Medical Statistics, Brussels (Belgium); Vlassenbroek, Alain [CT Clinical Science, Philips Medical Systems, Cleveland, OH (United States)

    2007-04-15

    Subjective and objective image quality (IQ) criteria, radiation doses, and acquisition times were compared using incremental monoslice, incremental multislice, and helical multislice acquisition techniques for routine unenhanced brain computed tomography (CT). Twenty-four patients were examined by two techniques in the same imaging session using a 16-row CT system equipped with 0.75-width detectors. Contiguous ''native'' 3-mm-thick slices were reconstructed for all acquisitions from four detectors for each slice (4 x 0.75 mm), with one channel available per detector. Two protocols were tailored to compare: (1) one-slice vs four-slice incremental images; (2) incremental vs helical four-slice images. Two trained observers independently scored 12 subjective items of IQ. Preference for the technique was assessed by one-tailed t test and the interobserver variation by two-tailed t test. The two observers gave very close IQ scores for the three techniques without significant interobserver variations. Measured IQ parameters failed to reveal any difference between techniques, and an approximate half radiation dose reduction was obtained by using the full 16-row configuration. Acquisition times were cumulatively shortened by using the multislice and the helical modality. (orig.)

  4. Suitability of helical multislice acquisition technique for routine unenhanced brain CT: an image quality study using a 16-row detector configuration

    International Nuclear Information System (INIS)

    Hernalsteen, Danielle; Cosnard, Guy; Grandin, Cecile; Duprez, Thierry; Robert, Annie; Vlassenbroek, Alain

    2007-01-01

    Subjective and objective image quality (IQ) criteria, radiation doses, and acquisition times were compared using incremental monoslice, incremental multislice, and helical multislice acquisition techniques for routine unenhanced brain computed tomography (CT). Twenty-four patients were examined by two techniques in the same imaging session using a 16-row CT system equipped with 0.75-width detectors. Contiguous ''native'' 3-mm-thick slices were reconstructed for all acquisitions from four detectors for each slice (4 x 0.75 mm), with one channel available per detector. Two protocols were tailored to compare: (1) one-slice vs four-slice incremental images; (2) incremental vs helical four-slice images. Two trained observers independently scored 12 subjective items of IQ. Preference for the technique was assessed by one-tailed t test and the interobserver variation by two-tailed t test. The two observers gave very close IQ scores for the three techniques without significant interobserver variations. Measured IQ parameters failed to reveal any difference between techniques, and an approximate half radiation dose reduction was obtained by using the full 16-row configuration. Acquisition times were cumulatively shortened by using the multislice and the helical modality. (orig.)

  5. Technological features and clinical feasibility of megavoltage CT scanning

    International Nuclear Information System (INIS)

    Nakagawa, Keiichi; Aoki, Yukimasa; Akanuma, Atsuo; Sakata, Kouichi; Karasawa, Katsuyuki; Terahara, Atsurou; Onogi, Yuzou; Hasezawa, Kenji; Sasaki, Yasuhito

    1992-01-01

    Megavoltage CT scanning using 4-MV and 6-MV radiotherapy beams has been developed and applied to verify errors in patient positioning. A detector system composed of 120 pairs of cadmium tungstate scintillators with photodiodes is mounted to the treatment unit at a distance of 160 cm from the beam source. Image reconstruction is performed with a standard filtered back-projection algorithm. Scanning time and reconstruction time for a slice is approximately 35 s and 60 s respectively. Although spatial resolution is as large as 4 mm, it has sufficient image quality to be applied for treatment planning and verification. The delivered dose with 4 MV and 6 MV is about 1.4 cGy and 2.8 cGy respectively. When a megavoltage CT image is taken in treatment position, the positioning errors are easily detected by comparing it with diagnostic CT sections for treatment planning. Several clinical examples are presented. (orig.)

  6. Centre for Industrial Application of CT scanning (CIA-CT) – Four years of results 2009-2013

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Andreasen, Jan Lasson; Christensen, Lars Bager

    activities: Centre of Excellence, Dissemination, Collaboration, Research, and Initiation of new activities. The consortium has consisted of nine partners, including three research institutions, two consultancy partners, two large companies, and two small / medium enterprises. The consortium has acted......The innovation consortium project, carried out September 2009 – August 2013, has aimed to help the participating companies and Danish industry with the introduction of CT scanning as measuring technology, carrying out research at international level. The project has operated through five main...... as a centre of excellence for industrial CT scanning, both nationally and internationally. A network with approx. 40 participants has been established, and a total of 22 students have been educated. Dissemination activities have encompassed: a web page www.cia-ct.mek.dtu.dk , 8 newsletters, 4 topical...

  7. A STUDY OF CORRELATION BETWEEN NASAL ENDOSCOPY AND CT SCAN IN CASES OF CHRONIC RHINOSINUSITIS

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    2015-07-01

    Full Text Available BACKGROUND: The accurate diagnosis of Chronic Rhinosinusitis (CRS is still a challenge therefore, the American Academy of Otorhinolaryngology - Head and Neck Surgery (AAO - HNS 1 has met in a multidisciplinary encounter and formulated a consensus based on only clinical symptoms. The computed tomography (CT scan and the nasal endoscopy (NE were introduced to make an accurate diagnosis of CRS and verify the disease severity. AIM: The aim of this study is to make a correlation between nasal endoscopy and CT scan in cases of clinically diagnosed Chronic Rhinosinusitis patients. METHOD: A study was carried out on 90 patients at Jhalawar Medical College, Jhalawar (Raj. during Sept. 20 12 to Dec. 2014. Diagnostic Nasal Endoscopy and CT Scan PNS done in patients, suffering from Chronic Rhinosinusitis. As a classification instruments, Metson / Gliklich's classification was used to evaluate the tomographic diagnosis and the Stankiewicz / Chow' s classification to evaluate the endoscopic diagnosis of Chronic Rhinosinusitis. RESULTS: Our study showed high specificity of endoscopy in comparison to CT scan though CT scan results are more sensitive. CONCLUSION: Endoscopy can confirm a Chronic Rhinosi nusitis diagnosis, but cannot rule it out, and that CT should be performed in cases of suspected CRS even if mucopurulence is not noted on endoscopy. The CT scan and the nasal endoscopy making easier the treatment planning and the disease resolution.

  8. Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration

    International Nuclear Information System (INIS)

    Wolthaus, J. W. H.; Sonke, J.-J.; Herk, M. van; Damen, E. M. F.

    2008-01-01

    Purpose: lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. Methods and Materials: 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Results: Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods <0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good

  9. Helical tomotherapy. Experiences of the first 150 patients in Heidelberg

    Energy Technology Data Exchange (ETDEWEB)

    Sterzing, F.; Schubert, K.; Sroka-Perez, G.; Kalz, J.; Debus, J.; Herfarth, K. [Dept. of Radiation Oncology, Univ. of Heidelberg (Germany)

    2008-01-15

    Background and purpose: helical tomotherapy was introduced into clinical routine at the Department of Radiation Oncology, University Hospital of Heidelberg, Germany, in July 2006. This report is intended to describe the experience with the first 150 patients treated with helical tomotherapy. Patient selection, time effort, handling of daily image guidance with megavoltage (MV) CT, and quality of radiation plans shall be assessed. Patients and methods: between July 2006 and May 2007, 150 patients were treated with helical tomotherapy in the University Hospital of Heidelberg. Mean age was 60 years with a minimum of 30 years and a maximum of 85 years. 79 of these patients received radiotherapy as a part of multimodal treatment pre- or postoperatively, 17 patients received treatment as a combined radiochemotherapy. 76% were treated with curative intent. Radiotherapy sites were central nervous system (n = 7), head and neck (n = 28), thoracic (n = 37), abdominal (n = 58) and skeletal system (n = 20). Most common tumor entities were prostate cancer (n = 28), breast cancer (n = 17), gastrointestinal tumors (n = 19), pharyngeal carcinoma (n = 14), lymphoma (n = 13), metastatic disease (bone n = 14, liver n = 6, lung n = 4, lymph node n = 2), sarcoma (n = 8), malignant pleural mesothelioma (n = 5), ovarian cancer treated with whole abdominal irradiation (n = 4), lung cancer (n = 3), skin malignancies (n = 3), chordoma (n = 2), meningioma (n = 2), one ependymoma and one medulloblastoma treated with craniospinal axis irradiation (n = 2), and others (n = 4). Nine patients were treated with single-fraction radiosurgery, nine with image-guided spinal reirradiation, and twelve patients were treated at multiple targets simultaneously. A pretreatment MV-CT scan was performed in 98.2% of the 3,026 fractions applied. After matching with the kilovoltage planning CT, corrections for translations and rotation around longitudinal axis (roll) were done. Results: mean time on table was 24

  10. CT SCAN EVALUATION OF PULMONARY NODULE

    Directory of Open Access Journals (Sweden)

    A. Ravi Kumar

    2016-06-01

    Full Text Available BACKGROUND Lung carcinomas are quite commonly diagnosed. Thanks to the ever increasing smokers’ population. Majority of the city dwellers are at a higher risk of having this disease when compared to the village counterparts. The stigma through which the person and the family have to undergo before confirming the diagnosis is enormous. So the radiographic methods of diagnosing the malignancies have to improve. Before confirming the diagnosis, the radiologists, the treating physicians should be somewhat confident about the diagnosis so as to prepare the patients and their relatives for the most probable diagnosis before the confirmatory report. The confirmatory procedures include the PET scan and the Histopathology. Both are time consuming procedures and in an economy like ours, finding a PET scanning centre is rather difficult. So the most probable diagnosis has to be thought of using minimal resource. This study puts in a sincere effort to understand and evaluate the pulmonary nodule when identified by a CT scan. This paper is intended to help the practicing radiologists and also make life easy for a practicing physician to identify correctly the lesions and also help the patients to prevent further progression of the disease. METHODS The study was a cross-sectional study. The sample size of the study consisted of thirty patients. CT scan was done in thirty patients who were identified to have lung nodules either by other mode of radiological studies or first time identified in a CT scan itself. The study was conducted in Fathima Institute of Medical Sciences, Kadapa. The study was conducted from 2014 to 2015. RESULT Non-solid nodules were more in number when compared to the solid nodules. All the non-solid nodules were confirmed to be adenomas. Eighty percent of the nodules which were more than 8 mm in size were confirmed to be malignant. One hundred percent of the spiculated border on CT was confirmed to be malignant. In the present study

  11. Dose profile study in head CT scans using a male anthropomorphic phantom

    International Nuclear Information System (INIS)

    Gomez, Alvaro M.L.; Santana, Priscila do C.; Mourao, Arnaldo P.

    2017-01-01

    Computed tomography (CT) test is an efficient and non-invasive method to obtain data about internal structures of the human body. CT scans contribute with the highest absorbed doses in population due X-ray beam attenuation and it has raised concern in radiosensitive tissues. Techniques for the optimization of CT scanning protocols in diagnostic services have been developing with the objective of decreasing the absorbed dose in the patient, aiming image quality within acceptable parameters for diagnosis by noise control. Routine head scans were performed using GE CT scan of 64 channels programmed with automatic exposure control and voltages of 80, 100 and 120 kV attaching the noise index in approximately 0.5%, using the tool of smart mA. An anthropomorphic adult male phantom was used and radiochromic film strips were placed to measure the absorbed dose deposited in areas such as the lens, thyroid and pituitary for study of dose deposited in these important areas containing high radiosensitive tissues. Different head scans were performed using optimized values of mA.s for the different voltages. The absorbed dose measured by the film strips were in the range of the 0.58 and 44.36 mGy. The analysis of noise in the images is within the acceptable levels for diagnosis, and the optimized protocol happens with the voltage of 100 kV. The use of other voltage values can allow obtain better protocols for head scans. (author)

  12. Dose profile study in head CT scans using a male anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Alvaro M.L.; Santana, Priscila do C.; Mourao, Arnaldo P., E-mail: amlgphys@gmail.com, E-mail: pridili@gmail.com, E-mail: apratabhz@gmail.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear; Centro Federal de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)

    2017-11-01

    Computed tomography (CT) test is an efficient and non-invasive method to obtain data about internal structures of the human body. CT scans contribute with the highest absorbed doses in population due X-ray beam attenuation and it has raised concern in radiosensitive tissues. Techniques for the optimization of CT scanning protocols in diagnostic services have been developing with the objective of decreasing the absorbed dose in the patient, aiming image quality within acceptable parameters for diagnosis by noise control. Routine head scans were performed using GE CT scan of 64 channels programmed with automatic exposure control and voltages of 80, 100 and 120 kV attaching the noise index in approximately 0.5%, using the tool of smart mA. An anthropomorphic adult male phantom was used and radiochromic film strips were placed to measure the absorbed dose deposited in areas such as the lens, thyroid and pituitary for study of dose deposited in these important areas containing high radiosensitive tissues. Different head scans were performed using optimized values of mA.s for the different voltages. The absorbed dose measured by the film strips were in the range of the 0.58 and 44.36 mGy. The analysis of noise in the images is within the acceptable levels for diagnosis, and the optimized protocol happens with the voltage of 100 kV. The use of other voltage values can allow obtain better protocols for head scans. (author)

  13. Percutaneous CT-guided lung biopsy: sequential versus spiral scanning. A randomized prospective study

    International Nuclear Information System (INIS)

    Ghaye, B.; Dondelinger, R.F.; Dewe, W.

    1999-01-01

    The aim of this study was to evaluate in a prospective and randomized study spiral versus sequential scanning in the guidance of percutaneous lung biopsy. Fifty thoracic lesions occurring in 48 patients were biopsied by a senior and a junior operator. Six different time segments of the procedure were measured. Scanning mode versus length of procedure, pathological results, irradiation and complications were evaluated. Total duration of the procedure and of the first sampling was significantly longer with spiral CT for the senior operator (p < 0.004). No significant time difference was observed for the junior operator. Diameter of the lesion, depth of location, position of the patient and needle entry site did not influence the results. The sensitivity was 90.9, specificity 100, positive predictive value 100 and negative predictive value 60 % for spiral CT, and 94.7, 100, 100 and 85.7 % for sequential CT, respectively. Eleven pneumothoraces and ten perinodular hemorrhages were seen with spiral CT and six and ten, respectively, with sequential CT. The mean dose of irradiation was 4027 mAs for spiral CT and 2358 mAs for conventional CT. Spiral CT does neither reduce procedure time nor the rate of complications. Pathological results do not differ compared with sequential CT, and total dose of irradiation is higher with spiral scanning. (orig.)

  14. Interactive lung segmentation in abnormal human and animal chest CT scans

    International Nuclear Information System (INIS)

    Kockelkorn, Thessa T. J. P.; Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

    2014-01-01

    Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

  15. CT scanning in patients with amputated legs

    International Nuclear Information System (INIS)

    Huebener, K.H.; Ahlemann, L.M.

    1981-01-01

    CT scanning after above-knee amputation and below-knee amputation helps to determine the calcium salt content of the examined bones, and to differentiate changes in the surrounding soft parts. By comaring the sides, it is quite easy to detect osteoporotic changes shortly after amputation which would otherwise remain undetected by X-ray film examination. It is equally easy to verify muscular changes, whereas characteristic changes in density allow to determine the share of vacant fat in muscular atrophy. Initial examinations proved the usefulness of CT diagnosis for early detection of dystrophic osseous and muscular changes and also show the possibilities of early therapy control of dystrophy treatment. (orig.) [de

  16. On the uncertainties in effective dose estimates of adult CT head scans

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

    2008-01-01

    Estimates of the effective dose to adult patients from computed tomography (CT) head scanning can be calculated using a number of different methods. These estimates can be used for a variety of purposes, such as improving scanning protocols, comparing different CT imaging centers, and weighing the benefits of the scan against the risk of radiation-induced cancer. The question arises: What is the uncertainty in these effective dose estimates? This study calculates the uncertainty of effective dose estimates produced by three computer programs (CT-EXPO, CTDosimetry, and ImpactDose) and one method that makes use of dose-length product (DLP) values. Uncertainties were calculated in accordance with an internationally recognized uncertainty analysis guide. For each of the four methods, the smallest and largest overall uncertainties (stated at the 95% confidence interval) were: 20%-31% (CT-EXPO), 15%-28% (CTDosimetry), 20%-36% (ImpactDose), and 22%-32% (DLP), respectively. The overall uncertainties for each method vary due to differences in the uncertainties of factors used in each method. The smallest uncertainties apply when the CT dose index for the scanner has been measured using a calibrated pencil ionization chamber

  17. Contribution of brain imaging techniques: CT-scan and magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Pasco-Papon, A.; Gourdier, A.L.; Papon, X.; Caron-Poitreau, C.

    1996-01-01

    In light of the current lack of consensus on the benefit of carotid artery surgery to treat asymptomatic carotid artery stenosis, the decision to operate on a patient depends on individual evaluation and characterization of risk factors on carotid artery stenosis greater than 70 %. The assessment of such risk factors is based especially on non-invasive brain imaging techniques.Computed tomography scanning (CT-scan) and magnetic resonance imaging (MRI) enable two types of stenosis to be differentiated, i.e. stenoses which are symptomatic and those that are radiologically proven versus those which are clinically and radiologically silent. CT-scan investigation (with and without injection of iodinated contrast media) still continues to be a common routine test in 1996 whenever a surgical revascularization procedure is planned. The presence of deep lacunar infarcts ipsilateral to the carotid artery stenosis generally evidence the reality of stenosis and thus are useful to the surgeon in establishing whether surgery is indicated. In the absence a consensus on indications for surgical management, the surgeon could use the CT-scan and MRI as medicolegal records which could be compared to a subsequent postoperative CT-scan in case of ischemic complications associated with the surgical procedure. Furthermore, recent cerebral ischemia as evidenced by filling with contrast material, will call for postponing treatment by a few weeks. Although conventional MRI is more contributive than brain CT-scan in terms of sensibility and specificity, its indications are narrower because of its limited availability and cost constraints. But, development of angio-MRI and functional imaging promise that its future is assured and even perhaps as the sole diagnostic method if its indications are expanded to include preoperative angiographic evaluation of atheromatous lesions of supra-aortic trunks. (authors). 37 refs

  18. Image quality of conventional images of dual-layer SPECTRAL CT: a phantom study.

    Science.gov (United States)

    van Ommen, F; Bennink, E; Vlassenbroek, A; Dankbaar, J W; Schilham, A M R; Viergever, M A; de Jong, H W A M

    2018-05-10

    Spectral CT using a dual layer detector offers the possibility of retrospectively introducing spectral information to conventional CT images. In theory, the dual-layer technology should not come with a dose or image quality penalty for conventional images. In this study, we evaluate the influence of a dual-layer detector (IQon Spectral CT, Philips) on the image quality of conventional CT images, by comparing these images with those of a conventional but otherwise technically comparable single-layer CT scanner (Brilliance iCT, Philips), by means of phantom experiments. For both CT scanners conventional CT images were acquired using four adult scanning protocols: i) body helical, ii) body axial, iii) head helical and iv) head axial. A CATPHAN 600 phantom was scanned to conduct an assessment of image quality metrics at equivalent (CTDI) dose levels. Noise was characterized by means of noise power spectra (NPS) and standard deviation (SD) of a uniform region, and spatial resolution was evaluated with modulation transfer functions (MTF) of a tungsten wire. In addition, contrast-to-noise ratio (CNR), image uniformity, CT number linearity, slice thickness, slice spacing, and spatial linearity were measured and evaluated. Additional measurements of CNR, resolution and noise were performed in two larger phantoms. The resolution levels at 50%, 10% and 5% MTF of the iCT and IQon showed small but significant differences up to 0.25 lp/cm for body scans, and up to 0.2 lp/cm for head scans in favor of the IQon. The iCT and IQon showed perfect CT linearity for body scans, but for head scans both scanners showed an underestimation of the CT numbers of materials with a high opacity. Slice thickness was slightly overestimated for both scanners. Slice spacing was comparable and reconstructed correctly. In addition, spatial linearity was excellent for both scanners, with a maximum error of 0.11 mm. CNR was higher on the IQon compared to the iCT for both normal and larger phantoms with

  19. Aphasia caused by intracerebral hemorrhage; CT-scan findings and prognosis

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Kazuhide; Segawa, Hiromu; Shiokawa, Yoshiaki; Hasegawa, Isao; Sano, Keiji (Fuji Brain Institute and Hospital, Shizuoka (Japan))

    1992-10-01

    It is generally accepted that cases of aphasia can be divided into several groups according to verbal fluency, auditory comprehension, and repetition abilities. Although many authors have studied aphasia and its location by means of a CT scan, the primary lesion on a CT scan with regard to the subtypes of aphasia still remains controversial. In this report we present our new CT classification for the syndromes of aphasia and the prognosis. Twenty-one patients with intracerebral hematoma (ICH) were followed up for more than 3 months after onset. ICH was classified according to the mode of the horizontal extension of the hematoma on a CT scan. Four lines were decided as follows: Line (a) is between the anterior horn of the lateral ventricle and the midpoint of the third ventricle; Line (b) is the vertical line to the saggital line which originates from the midpoint of the third ventricle; Line (c) is between the trigone of the lateral ventricle and the midpoint of the third ventricle. The CT classification consisted of 4 types: in Type A, ICH was located anterior to line (a); in Type B, ICH was located between line (a) and line (b); in Type C, ICH was located between line (b) and line (c); Type B+C, was a combination of Type B and Type C. Transcortical motor aphasia belonged to the Type A group. Transcortical sensory aphasia belonged to the Type B and Type B+C groups. Wernicke's and anomic aphasia belonged to the Type C group. Conduction and global aphasia belonged to the Type B+C group. Pure Broca's aphasia could not be observed in this series. Several relationships between the syndromes of aphasia and its CT findings were evident. On the other hand, the syndromes of aphasia and the degree of recovery were not correlated, except for global aphasia. (author).

  20. Aphasia caused by intracerebral hemorrhage; CT-scan findings and prognosis

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Kazuhide; Segawa, Hiromu; Shiokawa, Yoshiaki; Hasegawa, Isao; Sano, Keiji [Fuji Brain Institute and Hospital, Shizuoka (Japan)

    1992-10-01

    It is generally accepted that cases of aphasia can be divided into several groups according to verbal fluency, auditory comprehension, and repetition abilities. Although many authors have studied aphasia and its location by means of a CT scan, the primary lesion on a CT scan with regard to the subtypes of aphasia still remains controversial. In this report we present our new CT classification for the syndromes of aphasia and the prognosis. Twenty-one patients with intracerebral hematoma (ICH) were followed up for more than 3 months after onset. ICH was classified according to the mode of the horizontal extension of the hematoma on a CT scan. Four lines were decided as follows: Line (a) is between the anterior horn of the lateral ventricle and the midpoint of the third ventricle; Line (b) is the vertical line to the saggital line which originates from the midpoint of the third ventricle; Line (c) is between the trigone of the lateral ventricle and the midpoint of the third ventricle. The CT classification consisted of 4 types: in Type A, ICH was located anterior to line (a); in Type B, ICH was located between line (a) and line (b); in Type C, ICH was located between line (b) and line (c); Type B+C, was a combination of Type B and Type C. Transcortical motor aphasia belonged to the Type A group. Transcortical sensory aphasia belonged to the Type B and Type B+C groups. Wernicke's and anomic aphasia belonged to the Type C group. Conduction and global aphasia belonged to the Type B+C group. Pure Broca's aphasia could not be observed in this series. Several relationships between the syndromes of aphasia and its CT findings were evident. On the other hand, the syndromes of aphasia and the degree of recovery were not correlated, except for global aphasia. (author).

  1. Evaluation of radiation dose and image quality of CT scan for whole-body pediatric PET/CT: A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ching-Ching, E-mail: cyang@tccn.edu.tw [Department of Medical Imaging and Radiological Sciences, Tzu-Chi College of Technology, 970, Hualien, Taiwan (China); Liu, Shu-Hsin [Department of Nuclear Medicine, Buddhist Tzu-Chi General Hospital, 970, Hualien, Taiwan and Department of Medical Imaging and Radiological Sciences, Tzu-Chi College of Technology, 970, Hualien, Taiwan (China); Mok, Greta S. P. [Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Wu, Tung-Hsin [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 112, Taipei, Taiwan (China)

    2014-09-15

    Purpose: This study aimed to tailor the CT imaging protocols for pediatric patients undergoing whole-body PET/CT examinations with appropriate attention to radiation exposure while maintaining adequate image quality for anatomic delineation of PET findings and attenuation correction of PET emission data. Methods: The measurements were made by using three anthropomorphic phantoms representative of 1-, 5-, and 10-year-old children with tube voltages of 80, 100, and 120 kVp, tube currents of 10, 40, 80, and 120 mA, and exposure time of 0.5 s at 1.75:1 pitch. Radiation dose estimates were derived from the dose-length product and were used to calculate risk estimates for radiation-induced cancer. The influence of image noise on image contrast and attenuation map for CT scans were evaluated based on Pearson's correlation coefficient and covariance, respectively. Multiple linear regression methods were used to investigate the effects of patient age, tube voltage, and tube current on radiation-induced cancer risk and image noise for CT scans. Results: The effective dose obtained using three anthropomorphic phantoms and 12 combinations of kVp and mA ranged from 0.09 to 4.08 mSv. Based on our results, CT scans acquired with 80 kVp/60 mA, 80 kVp/80 mA, and 100 kVp/60 mA could be performed on 1-, 5-, and 10-year-old children, respectively, to minimize cancer risk due to CT scans while maintaining the accuracy of attenuation map and CT image contrast. The effective doses of the proposed protocols for 1-, 5- and 10-year-old children were 0.65, 0.86, and 1.065 mSv, respectively. Conclusions: Low-dose pediatric CT protocols were proposed to balance the tradeoff between radiation-induced cancer risk and image quality for patients ranging in age from 1 to 10 years old undergoing whole-body PET/CT examinations.

  2. Helical CT findings of gastric wall thickening by peptic ulcer : compared with gastric adenocarcinoma with ulcer

    International Nuclear Information System (INIS)

    Jung, Won Jung; Choi, Jong Chul; Seo, Keum Soo; Koo, Bon Sik; Park, Byeong Ho; Kim, Chung Ku; Lee, Ki Nam; Nam, Kyung Jin

    2000-01-01

    To compare on the basis of helical CT findings gastric wall thickening of peptic gastric ulcer with that of gastric adenocarcinoma with ulcer. Thirty-eight patients with pathologically proven gastric lesion (17 cases of peptic ulcer and 21 cases of ulcerative or ulceroinfiltrative gastric cancer (Borrman type II, III) underwent helical CT, and the findings were retrospectively reviewed in terms of maximum abnormal wall thickness, preservation of the inner enhancing layer, the presence three discriminate layers of gastric wall, and enhancement pattern. The enhancement pattern of abnormally thick wall was compared with that of the portal phase of back muscle, and was defined as low, iso, or high. The Chi-square test and Student t test were used for statistical analysis. In cases of peptic ulcer and gastric cancer with ulceration, maximum abnormal wall thickness was 7-30 (mean, 16.1)mm, and 11-33 (mean, 21.8)mm, respectively. The inner enhancing layer was preserved in 15 of 17 patients (88.2%) and one of 21 (4.8%); three discriminate layers of gastric wall were observed in 8 of 17 patients (47.0%), and one of 21 (4.8%). The enhancement pattern was low in 12 of 17 patients (70.5%), and 3 of 21 (14.3%); iso in 4 of 17 (23.5%), and 4 of 21 (19.0%), and high in one of 17 (5.9%), and 14 of 21 (66.7%). All figures refer, respectively, to the two distinct conditions. In terms of preservation of the inner enhancing layer, three discriminate layers of gastric wall, and a low enhancement pattern, there were statistically significant differences between peptic ulcer and gastric adenocarcinoma with ulcer. Where the enhancement was high, however, the statistically significant difference between the two conditions was even greater. There was no statistically significant difference in terms of gastric wall thickness or iso-attenuation of thickened gastric. Helical CT findings of gastric wall thickening, preservation of the inner enhancing layer, and three discriminate layers of

  3. Helical CT findings of gastric wall thickening by peptic ulcer : compared with gastric adenocarcinoma with ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Won Jung; Choi, Jong Chul; Seo, Keum Soo; Koo, Bon Sik; Park, Byeong Ho; Kim, Chung Ku; Lee, Ki Nam; Nam, Kyung Jin [College of Medicine, Dong A University, Pusan (Korea, Republic of)

    2000-02-01

    To compare on the basis of helical CT findings gastric wall thickening of peptic gastric ulcer with that of gastric adenocarcinoma with ulcer. Thirty-eight patients with pathologically proven gastric lesion (17 cases of peptic ulcer and 21 cases of ulcerative or ulceroinfiltrative gastric cancer (Borrman type II, III)) underwent helical CT, and the findings were retrospectively reviewed in terms of maximum abnormal wall thickness, preservation of the inner enhancing layer, the presence three discriminate layers of gastric wall, and enhancement pattern. The enhancement pattern of abnormally thick wall was compared with that of the portal phase of back muscle, and was defined as low, iso, or high. The Chi-square test and Student t test were used for statistical analysis. In cases of peptic ulcer and gastric cancer with ulceration, maximum abnormal wall thickness was 7-30 (mean, 16.1)mm, and 11-33 (mean, 21.8)mm, respectively. The inner enhancing layer was preserved in 15 of 17 patients (88.2%) and one of 21 (4.8%); three discriminate layers of gastric wall were observed in 8 of 17 patients (47.0%), and one of 21 (4.8%). The enhancement pattern was low in 12 of 17 patients (70.5%), and 3 of 21 (14.3%); iso in 4 of 17 (23.5%), and 4 of 21 (19.0%), and high in one of 17 (5.9%), and 14 of 21 (66.7%). All figures refer, respectively, to the two distinct conditions. In terms of preservation of the inner enhancing layer, three discriminate layers of gastric wall, and a low enhancement pattern, there were statistically significant differences between peptic ulcer and gastric adenocarcinoma with ulcer. Where the enhancement was high, however, the statistically significant difference between the two conditions was even greater. There was no statistically significant difference in terms of gastric wall thickness or iso-attenuation of thickened gastric. Helical CT findings of gastric wall thickening, preservation of the inner enhancing layer, and three discriminate layers of

  4. TU-F-BRF-03: Effect of Radiation Therapy Planning Scan Registration On the Dose in Lung Cancer Patient CT Scans

    International Nuclear Information System (INIS)

    Cunliffe, A; Contee, C; White, B; Justusson, J; Armato, S; Malik, R; Al-Hallaq, H

    2014-01-01

    Purpose: To characterize the effect of deformable registration of serial computed tomography (CT) scans on the radiation dose calculated from a treatment planning scan. Methods: Eighteen patients who received curative doses (≥60Gy, 2Gy/fraction) of photon radiation therapy for lung cancer treatment were retrospectively identified. For each patient, a diagnostic-quality pre-therapy (4–75 days) CT scan and a treatment planning scan with an associated dose map calculated in Pinnacle were collected. To establish baseline correspondence between scan pairs, a researcher manually identified anatomically corresponding landmark point pairs between the two scans. Pre-therapy scans were co-registered with planning scans (and associated dose maps) using the Plastimatch demons and Fraunhofer MEVIS deformable registration algorithms. Landmark points in each pretherapy scan were automatically mapped to the planning scan using the displacement vector field output from both registration algorithms. The absolute difference in planned dose (|ΔD|) between manually and automatically mapped landmark points was calculated. Using regression modeling, |ΔD| was modeled as a function of the distance between manually and automatically matched points (registration error, E), the dose standard deviation (SD-dose) in the eight-pixel neighborhood, and the registration algorithm used. Results: 52–92 landmark point pairs (median: 82) were identified in each patient's scans. Average |ΔD| across patients was 3.66Gy (range: 1.2–7.2Gy). |ΔD| was significantly reduced by 0.53Gy using Plastimatch demons compared with Fraunhofer MEVIS. |ΔD| increased significantly as a function of E (0.39Gy/mm) and SD-dose (2.23Gy/Gy). Conclusion: An average error of <4Gy in radiation dose was introduced when points were mapped between CT scan pairs using deformable registration. Dose differences following registration were significantly increased when the Fraunhofer MEVIS registration algorithm was used

  5. Dual-phase helical CT using bolus triggering technique: optimization of transition time

    International Nuclear Information System (INIS)

    Choi, Young Ho; Kim, Tae Kyoung; Park, Byung Kwan; Koh, Young Hwan; Han, Joon Koo; Choi, Byung Ihn

    1999-01-01

    To optimize the transition time between the triggering point in monitoring scanning and the initiation of diagnostic hepatic arterial phase (HAP) scanning in hepatic spiral CT, using a bolus triggering technique. One hundred consecutive patients with focal hepatic lesion were included in this study. Patients were randomized into two groups. Transition times of 7 and 11 seconds were used in group 1 and 2, respectively. In all patients, bolus triggered HAP spiral CT was obtained using a semi-automatic bolus tracking program after the injection of 120mL of non-ionic contrast media at a rate of 3mL/sec. When aortic enhancement reached 90 HU, diagnostic HAP scanning began after a given transition time. From images of group 1 and group 2, the degree of parenchymal enhancement of the liver and tumor-to-liver attenuation difference were measured. Also, for qualitative analysis, conspicuity of the hepatic artery and hypervascular tumor was scored and analyzed. Hepatic parenchymal enhancement on HAP was 12.07 + /-6.44 HU in group 1 and 16.03 + /-5.80 HU in group 2 (p .05). In the evaluation of conspicuity of hepatic artery, there was no statistically significant difference between the two groups (p > .05). The conspicuity of hypervascular tumors in group 2 was higher than in group 1 (p < .05). HAP spiral CT using a bolus triggering technique with a transition time of 11 seconds provides better HAP images than when the transition time is 7 seconds

  6. High-resolution CT of otosclerosis

    International Nuclear Information System (INIS)

    Dewen, Yang; Kodama, Takao; Tono, Tetsuya; Ochiai, Reiji; Kiyomizu, Kensuke; Suzuki, Yukiko; Yano, Takanori; Watanabe, Katsushi

    1997-01-01

    High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labyrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected. (author)

  7. Synthetic display of three-dimensional CT and MPR for gastric neoplasm

    International Nuclear Information System (INIS)

    Ogura, Toshihiro; Maruyama, Masakazu

    1998-01-01

    We attempted to obtain synthesized three dimensional (3D) and MPR (Multi Planar Reconstruction) helical CT scans (3D-MPR-CT) of gastric neoplasm by using the air as a contrast medium, and we assessed the usefulness of 3D-MPR-CT gastroendoscopy in the diagnosis of gastric neoplasm. Five minutes before the scan, 20 mg Scopolamine Butylbromide (Buscopan) was injected intramuscularly to minimize gastric peristalsis. An effervescent agent (bubble-make granules) was fed to extend the stomach wall. Non-ionic contrast material (100 mL) was power injected immediately before the scan start. Axial images were obtained with an intersection gap of 5-mm, a 5-mm/sec table speed, and 1-mm reconstruction intervals. 3D-MPR-CT images were reconstructed from these images. In abdominal study, 3D-MPR-CT images enabled the visualization of neoplasm and its adjacent structures in versatile directions, including a view similar to endoscopic observation, proximal aspect of narrowing by tumor and also could get the information about invasive depth of gastric neoplasm. Reports on some clinical cases and the advantages and disadvantages of 3D-MPR-CT gastroendoscopy were discussed. (author)

  8. Evaluation of normal brain CT scan in Korean

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Suh, J. H.; Park, C. Y. [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1981-06-15

    The safety of procedure combined with wealth of information have resulted in rapid acceptance of CT as a practical and reliable neurodignostic technique. To understand the alternation in tissue density and associated displacement and distortion caused by pathologic lesion in CT, it is necessary to have clear understanding of normal anatomical landmark. For the purpose of establishing normative criteria in Korean for comparative diagnosis, 500 normal CT scan without neurologic sign were studied. The brief results are follows; 1. Among many ventricular index measured for lateral ventricle, the bifrontal CVI is more sensitive and easily determined. Ventricular size increased with age, especially after 6th decade but no difference with sex. 2. Mean width of third ventricle is 5 mm ({+-} 0.3), more wider in male (male; 5.2 mm, female; 4.5 mm) and increased with age. 2. Mean width of fourth ventricle is 13 mm ({+-} 1.3), without difference in age and sex. The shape of ventricle is variable form of triangle. The position of ventricle relative to Twining's line can be determined, so ratio of distance from tuberculum sellae to center of fourth ventricle to Twining's line is between 0.46-0.52. 4. Suprasellar cistern is visible in 89.7% of scan and shape of cistern is found to be pentagonal (73.3%), hexagonal (23.0%) and tetragonal (3.7%). 5. Choroid plexus can be identified in 90% and asymmetrical in 4%. 45% of identified choroid plexus can be visible on scan without contrast enhancement, and more frequently visible in older age.

  9. Evaluation of normal brain CT scan in Koreans

    International Nuclear Information System (INIS)

    Lee, Y. H.; Suh, J. H.; Park, C. Y.

    1981-01-01

    The safety of procedure combined with wealth of information have resulted in rapid acceptance of CT as a practical and reliable neurodiagnostic technique. To understand the alternation in tissue density and associated displacement and distortion caused by pathologic lesion in CT, it is necessary to have clear understanding of normal anatomical landmark. For the purpose of establishing normartive criteria in Koreans for comparative diagnosis, 500 normal CT scan without neurologic sign were studied. The brief results are follows; 1. Among many ventricular index measured for lateral ventricle, the bifrontal CVI is more sensitive and easily determined. Ventricular size increased with age, especially after 6th decade but no difference with sex. 2. Mean width of third ventricle is 5mm( ± 0.3), more wider in male (male; 5.2mm, female; 4.5mm) and increased with age. 3. Mean width of fourth ventricle is 13mm( ± 1.3), without difference in age and sex. The shape of ventricle is variable form of triangle. The position of ventricle relative to Twining's line can be determined, so ratio of distance from tuberculum sellae to center of fourth ventricle to Twining's line is between 0.46-0.52. 4. Suprasellar cistern is visible in 89.7% of scan and shape of cistern is found to be pentagonal (73.3%), hexagonal (23.0%) and tetragonal (3.7%). 5. Choroid plexus can be identified in 90% and asymetrical in 4%. 45% of identified choroid plexus can be visible on scan without contrast enhancement, and more frequently visible in older age

  10. Evaluation of normal brain CT scan in Korean

    International Nuclear Information System (INIS)

    Lee, Y. H.; Suh, J. H.; Park, C. Y.

    1981-01-01

    The safety of procedure combined with wealth of information have resulted in rapid acceptance of CT as a practical and reliable neurodignostic technique. To understand the alternation in tissue density and associated displacement and distortion caused by pathologic lesion in CT, it is necessary to have clear understanding of normal anatomical landmark. For the purpose of establishing normative criteria in Korean for comparative diagnosis, 500 normal CT scan without neurologic sign were studied. The brief results are follows; 1. Among many ventricular index measured for lateral ventricle, the bifrontal CVI is more sensitive and easily determined. Ventricular size increased with age, especially after 6th decade but no difference with sex. 2. Mean width of third ventricle is 5 mm (± 0.3), more wider in male (male; 5.2 mm, female; 4.5 mm) and increased with age. 2. Mean width of fourth ventricle is 13 mm (± 1.3), without difference in age and sex. The shape of ventricle is variable form of triangle. The position of ventricle relative to Twining's line can be determined, so ratio of distance from tuberculum sellae to center of fourth ventricle to Twining's line is between 0.46-0.52. 4. Suprasellar cistern is visible in 89.7% of scan and shape of cistern is found to be pentagonal (73.3%), hexagonal (23.0%) and tetragonal (3.7%). 5. Choroid plexus can be identified in 90% and asymmetrical in 4%. 45% of identified choroid plexus can be visible on scan without contrast enhancement, and more frequently visible in older age

  11. Clinical applications for multiplanar- and three-dimensional-reconstructions by helical-CT for the diagnosis of acetabular fractures

    International Nuclear Information System (INIS)

    Stroszczynski, C.; Schedel, H.; Stoeckle, U.; Wellmann, A.; Beier, J.; Wicht, L.; Hoffmann, R.; Felix, R.

    1996-01-01

    This review describes recent visualizations of computed tomography for the diagnosis of acetabular fractures. The techniques of conventional and helical-CT for the imaging of the acetabulum are compared. Furthermore, the different methods of multiplaner and three-dimensional reconstructions e.g. shaded surface display, maximum intensity projection, and volume rendering are presented. Figures of multiplanar and three-dimensional imaging for fractures of the pelvis is discussed. (orig.) [de

  12. The use of the eyes protection for dose reduction in CT scans of skull

    International Nuclear Information System (INIS)

    Mourao, Arnaldo P.; Silva, Teogenes A.; Alonso, Thessa C.

    2013-01-01

    The technique for imaging the brain scans of the skull by computed tomography (CT) scanning is the volume bounded by the foramen magnum and the apex of the skull. The lenses are radiosensitive tissues and CT scans of the head deposited significant doses on them, since they are in the region of incidence of the primary beam of X-rays. Thus, the variation of the dose deposited in the crystalline skull CT scans for diagnostic imaging of the brain was investigated. Cranial scans were performed using the acquisition protocol routine with or without the use of bismuth to shield the eyes. To carry out the scans we used a male anthropomorphic phantom, Alderson Rando model and dosimeters (TLD-100) were used to record the doses. These TLDs were used to record specific doses internally to the phantom in specific organs (crystalline, pituitary, thyroid, spinal cord and breasts). The scans were performed on a GE machine, model 64 Discovery channels. The data obtained allowed to observe the variation of dose in organs. The highest dose was recorded in the lens (26,18 mGy), followed by spinal cord (17,79 mGy). Comparing the doses of the two scans it was significant variation in the crystal. Scan using bismuth shield generated smaller doses in the eyes and in the eyes occurred the higher dose reduction, about 37%. The results may contribute to spread a suitable procedure for the optimization of CT scans of the skull

  13. CT-scanning of ancient Greenlandic Inuit temporal bones

    DEFF Research Database (Denmark)

    Homøe, P; Lynnerup, N; Videbaek, H

    1992-01-01

    Additional morphological evidence of former infectious middle ear disease (IMED) was found by CT-scanning in 5 of 6 Greenlandic Inuit crania strongly suspected for former IMED due to earlier examination revealing either bilateral hypocellularity or asymmetry of the pneumatized area of the temporal...

  14. Dosimetric comparison of stereotactic body radiotherapy using 4D CT and multiphase CT images for treatment planning of lung cancer: Evaluation of the impact on daily dose coverage

    International Nuclear Information System (INIS)

    Wang Lu; Hayes, Shelly; Paskalev, Kamen; Jin Lihui; Buyyounouski, Mark K.; Ma, Charlie C.-M.; Feigenberg, Steve

    2009-01-01

    Purpose: To investigate the dosimetric impact of using 4D CT and multiphase (helical) CT images for treatment planning target definition and the daily target coverage in hypofractionated stereotactic body radiotherapy (SBRT) of lung cancer. Materials and methods: For 10 consecutive patients treated with SBRT, a set of 4D CT images and three sets of multiphase helical CT scans, taken during free-breathing, end-inspiration and end-expiration breath-hold, were obtained. Three separate planning target volumes (PTVs) were created from these image sets. A PTV 4D was created from the maximum intensity projection (MIP) reconstructed 4D images by adding a 3 mm margin to the internal target volume (ITV). A PTV 3CT was created by generating ITV from gross target volumes (GTVs) contoured from the three multiphase images. Finally, a third conventional PTV (denoted PTV conv ) was created by adding 5 mm in the axial direction and 10 mm in the longitudinal direction to the GTV (in this work, GTV = CTV = clinical target volume) generated from free-breathing helical CT scans. Treatment planning was performed based on PTV 4D (denoted as Plan-1), and the plan was adopted for PTV 3CT and PTV conv to form Plan-2 and Plan-3, respectively, by superimposing 'Plan-1' onto the helical free-breathing CT data set using modified beam apertures that conformed to either PTV 3CT or PTV conv . We first studied the impact of PTV design on treatment planning by evaluating the dosimetry of the three PTVs under the three plans, respectively. Then we examined the effect of the PTV designs on the daily target coverage by utilizing pre-treatment localization CT (CT-on-rails) images for daily GTV contouring and dose recalculation. The changes in the dose parameters of D 95 and D 99 (the dose received by 95% and 99% of the target volume, respectively), and the V p (the volume receiving the prescription dose) of the daily GTVs were compared under the three plans before and after setup error correction

  15. A new method of CT scanning for the diagnosis of mandibular fractures

    International Nuclear Information System (INIS)

    Tsukagoshi, Taku; Satoh, Kaneshige; Onizuka, Takuya

    1990-01-01

    The condylar neck of the mandible is one of the most common fracture sites in the facial skeleton. Such a fracture is routinely diagnosed by A-P, lateral oblique, and Towne projection roentgenography or orthopantomography. Despite the combination of these films, fracture of the neck of the mandible is still difficult to diagnose definitely. Therefore, a new CT scanning method was developed for diagnosing fractures of the neck of the condylar mandible. The CT axis is projected along the length of the mandible, extending from the condyle to the symphysis. This projection visualizes both the condyle and the mandibular symphysis in the same plane. The patient is placed in a supine position with the head fully extended. The base line, a line extending from the midpoint of the glenoid fossa to the menton, is determined with a lateral facial cephalogram. CT scanning with a 5 mm window is performed in parallel with and 2 cm anterior to and 2 cm posterior to the base line. When CT scanning was performed in a healthy volunteer, the condition of the condyle and the condylar neck of the mandible was clearly shown, and the view extended from the condyle to the symphysis. For automobile accident patients in whom fracture of the neck of the mandible was associated with fracture of the symphysis, two fractures were found in the same plane. A newly developed CT scanning technique is useful in the diagnosis of fractures of the condylar neck of the mandible and in the identification of fractures at other mandibular sites. It also allows scanning of patients in a supine position, which may aid in managing patients with multiple traumas. (N.K.)

  16. Value of CT scanning in radiation therapy treatment planning: a prospective study

    International Nuclear Information System (INIS)

    Goitein, M.; Wittenberg, J.; Mendiondo, M.; Doucette, J.; Friedberg, C.; Ferrucci, J.; Gunderson, L.; Linggood, R.; Shipley, W.U.; Fineberg, H.V.

    1979-01-01

    We report the results of a prospective study in which we assessed the value of computed tomography (CT) scanning in planning radiation therapy for 77 patients. First, conventional studies were performed, treatment fields were designed and simulated and, where appropriate, computer generated treatment plans drawn up. Then a CT scan was performed to delineate the location of the tumor and adjacent uninvolved tissues. The treatment goals and plans were reevaluated and changed when necessary. Forty of the 77 patients (52%) had their treatment changed as a result of the CT scan. Of these, four (5%) had a change of treatment modality. Thirty-two patients (42%) had changes in the radiotherapy technique because of inadequate tumor coverage (in 24 patients (31%) part of the tumor was outside one or more of the fields and in the other 8 patients (10%) the tumor coverage was marginal). Field changes resulting only from considerations of normal tissue coverage were made for 4 of these patients (5%). In total, normal tissue coverage was affected in 36 patients (47%). When the significance of these changes was evaluated, CT scanning was judged to be of major value for 28 of the 77 patients (36%) and of minor value in a further 12 patients

  17. Effects of megavoltage computed tomographic scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy.

    Science.gov (United States)

    Zhu, Jian; Bai, Tong; Gu, Jiabing; Sun, Ziwen; Wei, Yumei; Li, Baosheng; Yin, Yong

    2018-04-27

    To evaluate the effect of pretreatment megavoltage computed tomographic (MVCT) scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy. Both anthropomorphic heterogeneous chest and pelvic phantoms were planned with virtual targets by TomoTherapy Physicist Station and were scanned with TomoTherapy megavoltage image-guided radiotherapy (IGRT) system consisted of six groups of options: three different acquisition pitches (APs) of 'fine', 'normal' and 'coarse' were implemented by multiplying 2 different corresponding reconstruction intervals (RIs). In order to mimic patient setup variations, each phantom was shifted 5 mm away manually in three orthogonal directions respectively. The effect of MVCT scan options was analyzed in image quality (CT number and noise), adaptive dose calculation deviations and positional correction variations. MVCT scanning time with pitch of 'fine' was approximately twice of 'normal' and 3 times more than 'coarse' setting, all which will not be affected by different RIs. MVCT with different APs delivered almost identical CT numbers and image noise inside 7 selected regions with various densities. DVH curves from adaptive dose calculation with serial MVCT images acquired by varied pitches overlapped together, where as there are no significant difference in all p values of intercept & slope of emulational spinal cord (p = 0.761 & 0.277), heart (p = 0.984 & 0.978), lungs (p = 0.992 & 0.980), soft tissue (p = 0.319 & 0.951) and bony structures (p = 0.960 & 0.929) between the most elaborated and the roughest serials of MVCT. Furthermore, gamma index analysis shown that, compared to the dose distribution calculated on MVCT of 'fine', only 0.2% or 1.1% of the points analyzed on MVCT of 'normal' or 'coarse' do not meet the defined gamma criterion. On chest phantom, all registration errors larger than 1 mm appeared at superior-inferior axis, which cannot be avoided with the smallest AP and RI

  18. Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

    Science.gov (United States)

    An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

  19. Four cases with localized brain-stem lesion on CT scan following closed head injury

    International Nuclear Information System (INIS)

    Saeki, Naokatsu; Odaki, Masaru; Oka, Nobuo; Takase, Manabu; Ono, Junichi.

    1981-01-01

    Cases of primary brain-stem injury following closed head injury, verified by a CT scan, have been increasingly reported. However, most of them have other intracranial lesions in addition to the brain stem, resulting in a poor outcome. The CT scan of 200 cases with severe head injury-Araki's classification of types 3 and 4 - were analysed. Four cases out of them had localized brain-stem lesion without any other significant intracranial injury on a CT scan at the acute stage and had a better outcome than had previously been reported. In this analysis, these 4 cases were studied, and the CT findings, prognosis, and pathogenesis of the localized brain-stem injury were discussed. Follow-up CT of three cases, and taken one month or more later, showed diffuse cortical atrophy. This may indicate the presence of diffuse cerebral injury which could not be seen on CT scans at the acute stage. This atrophic change may also be related with the mechanism of posttraumatic conscious impairment and posttraumatic neurological deficits, such as mental symptoms and impairment of the higher cortical function. Shearing injury is a probable pathogenesis for this diffuse cortical injury. On the other hand, one case did not have any cortical atrophy on a follow-up CT scan. Therefore, this is a case with a localized primary brain-stem injury. Coup injury against the brain stem by a tentorial margin in a case with a small tentorial opening is a possible mechanism producing the localized brain-stem injury. (J.P.N.)

  20. Clinical features and CT scan findings of supratentorial ependymomas and ependymoblastomas

    International Nuclear Information System (INIS)

    Hanakita, Junya; Handa, Hajime

    1984-01-01

    The clinical courses and CT scan findings of 12 cases of supratentorial ependymoma and ependymoblastoma were reviewed. The age of the patient of ependymoma ranged from 3 years to 34 years, with an average age of 16 years. The follow-up time ranged from 2 months to 9 years and 10 months. All of the six patients are still alive. The age of the patients of ependymoblastoma ranged from 7 months to 34 years, with an average age of 17 years. During the follow-up period from 2 weeks to 6 years and 4 months, four patients died. Supratentorial ependymomas and ependymoblastomas show the following characteristic features of CT scans: 1. Calcification: The incidence of calcification was 50% in ependymoma-group, and 100% in ependymoblastoma-group. 2. Cyst formation, ring-enhancement: The cyst formation was noticed in both groups. In ependymoma-group a smooth ring-enhancement pattern and the strongly enhanced mural nodule-like contour were found, but in ependymoblastoma-group, the cyst wall was enhanced in irregular shape. 3. Perifocal edema and mass effect: Considerable mass effect was noticed in both groups. Perifocal edema was slight in many cases of ependymoma-group, but mostly prominent in ependymoblastoma-group. 4. CT scan findings of recurrent tumor: In ependymoma-group, recurrent tumor showed the same characteristics of CT scan as the initial ones. In ependymoblastoma-group, cystic portion decreased in size and irregular shaped solid portion increased in recurrence. (author)

  1. Evaluation of radiation doses delivered in different chest CT protocols

    International Nuclear Information System (INIS)

    Gorycki, Tomasz; Lasek, Iwona; Kamiński, Kamil; Studniarek, Michał

    2014-01-01

    There are differences in the reference diagnostic levels for the computed tomography (CT) of the chest as cited in different literature sources. The doses are expressed either in weighted CT dose index (CTDI VOL ) used to express the dose per slice, dose-length product (DLP), and effective dose (E). The purpose of this study was to assess the radiation dose used in Low Dose Computer Tomography (LDCT) of the chest in comparison with routine chest CT examinations as well as to compare doses delivered in low dose chest CT with chest X-ray doses. CTDI VOL and DLP doses were taken to analysis from routine CT chest examinations (64 MDCT TK LIGHT SPEED GE Medical System) performed in 202 adult patients with FBP reconstruction: 51 low dose, 106 helical, 20 angio CT, and 25 high resolution CT protocols, as well as 19 helical protocols with iterative ASIR reconstruction. The analysis of chest X-ray doses was made on the basis of reports from 44 examinations. Mean values of CTDI VOL and DLP were, respectively: 2.1 mGy and 85.1 mGy·cm, for low dose, 9.7 mGy and 392.3 mGy·cm for helical, 18.2 mGy and 813.9 mGy·cm for angio CT, 2.3 mGy and 64.4 mGy·cm for high resolution CT, 8.9 mGy. and 317.6 mGy·cm for helical ASIR protocols. Significantly lower CTDI VOL and DLP values were observed for low dose and high resolution CT versus the remaining CT protocols; doses delivered in CT ASIR protocols were also lower (80–81%). The ratio between medial doses in low dose CT and chest X-ray was 11.56. Radiation dose in extended chest LDCT with parameters allowing for identification of mediastinal structures and adrenal glands is still much lower than that in standard CT protocols. Effective doses predicted for LDCT may exceed those used in chest X-ray examinations by a factor of 4 to 12, depending on LDCT scan parameters. Our results, as well as results from other authors, suggest a possibility of reducing the dose by means of iterative reconstruction. Efforts towards further dose

  2. A case of Neuro-Behcet's disease with an interesting CT scan picture

    International Nuclear Information System (INIS)

    Sato, Jinichi; Kamitani, Hiroshi; Masuzawa, Hideaki; Matsui, Takayoshi; Mizobe, Masafumi.

    1981-01-01

    A Case of Neuro-Behcet's disease with an interesting CT scan picture was reported. A 31-year-old man with a known history of Behcet's disease was transferred to the Kantoh-Teishin Hospital upon suspicion of a brain tumor in the basal ganglia. Right hemiparesis and mild dysarthria of three weeks' duration and long-standing bilateral blindness were noted. Computerized tomography (CT) demonstrated an enhanced mass in the basal ganglia and surrounding irregular, low-density area in the white matter of the left frotoparietal lobe. The ventricles were shifted to the right. Left carotid angiography revealed a shift of the anterior cerebral artery to the right and a mild deformity of the Sylvian triangle. No tumor stain or abnormal vessels were seen. After high doses of prednisolone, his condition gradually improved. A CT scan two weeks later revealed a decrease in the low-density area and the mass effect, but an unchanged pathological contrast enhancement in the basal ganglia. The contrast enhancement lasted for two months. The CT scan of Neuro-Behcet's disease was discussed. (author)

  3. CT perfusion scanning of the brain in stroke and beyond

    International Nuclear Information System (INIS)

    Riedel, Christian

    2011-01-01

    CT perfusion scanning (CTP) allows for quantitative analysis of cerebral blood flow (CBF) and cerebral blood volume (CBV). Until recently, it was only possible to study brain perfusion parameters in a small stack of CT-slices close to the skull base. With the introduction of multidetector CT scanners with 64 and more detector rows it has become possible to assess perfusion of the entire brain. An optimal choice of scanning parameters like the new 'shuttle'-technique combined with a well adapted regimen for contrast administration is required to guarantee reliable perfusion measurements while still keeping the X-ray dose absorbed by the patient at a minimum. With these techniques, CTP is not only an important modality in the work-up of patients suffering from acute ischemic stroke but can also be valuable in other emergency situations such as in prolonged epileptic seizures or to monitor patients with subacute subarachnoid hemorrhage. (orig.)

  4. A comparison between intrastomal 3D ultrasonography, CT scanning and findings at surgery in patients with stomal complaints.

    Science.gov (United States)

    Näsvall, P; Wikner, F; Gunnarsson, U; Rutegård, J; Strigård, K

    2014-10-01

    Since there are no reliable investigative tools for imaging parastomal hernia, new techniques are needed. The aim of this study was to assess the validity of intrastomal three-dimensional ultrasonography (3D) as an alternative to CT scanning for the assessment of stomal complaints. Twenty patients with stomal complaints, indicating surgery, were examined preoperatively with a CT scan in the supine position and 3D intrastomal ultrasonography in the supine and erect positions. Comparison with findings at surgery, considered to be the true state, was made. Both imaging methods, 3D ultrasonography and CT scanning, showed high sensitivity (ultrasound 15/18, CT scan 15/18) and specificity (ultrasound 2/2, CT scan 1/2) when judged by a dedicated radiologist. Corresponding values for interpretation of CT scans in routine clinical practice was for sensitivity 17/18 and for specificity 1/2. 3D ultrasonography has a high validity and is a promising alternative to CT scanning in the supine position to distinguish a bulge from a parastomal hernia.

  5. Hereditary haemorrhagic telangiectasia: study of hepatic vascular alterations with multi-detector row helical CT and reconstruction programs

    International Nuclear Information System (INIS)

    Memeo, Maurizio; Stabile Ianora, Amato Antonio; Scaldapane, Arnaldo; Rotondo, Antonio; Angelelli, Giuseppe; Suppressa, Patrizia; Cirulli, Anna; Sabba', Carlo

    2005-01-01

    Purpose: To evaluate hepatic alterations in patients affected by Hereditary Haemorrhagic Telangiectasia (HHT) by using multidetector row helical CT (MDCT) and new reconstruction programs. Materials and methods: An MDCT multiphasic study of the liver was performed in 105 consecutive patients: 89 considered to be affected by HHT and 16 with suspicion of disease alone. The scan delay was determined by using a test bolus of contrast material. The CT examination was performed with a triphasic technique (double arterial phase and portal venous phase). multiplanar and angiographic reconstructions were then obtained, and the images checked for the presence of shunts, hepatic perfusion disorders, vascular lesions (telangiectasis and large confluent vascular masses), indirect signs of portal hypertension, and anatomical vascular variants. Results: Hepatic vascular alterations were found in 78/105 cases (67/89) patients affected by HHT and 11/16 patients with clinical suspicion alone). Therefore HHT diagnosis was excluded in 5 patients. 78/100 (78%) patients with HHT had intrahepatic vascular alterations: arterioportal shunts in 40/78 (51.2%) arteriosystemic shunts in 16/78 (20.5%) and both shunt types in 22/78 (28.3%). Intraparenchymal perfusion disorders were found in 46/78 (58.9%) patients. Telangiectasis were recognised in 50/78 (64.1%) patients. Large confluent vascular masses (LCVMs) were identified in 20/78 (25.6%) patients. indirect signs of portal hypertension were found in 46/78 (58.9%) cases. Variant hepatic arterial anatomy was present in 38/100 cases (38%). Conclusions: Multiphasic MDCT and the new reconstruction programs enable the identification and characterisation of the complex vascular alterations typical of HHT [it

  6. Subperiosteal chondroma. Diagnostic value of CT scan imaging in two cases

    International Nuclear Information System (INIS)

    Lerais, J.M.; Auquier, F.; Baudrillard, J.C.; Durot, J.F.; Laugareil, P.; Wallays, C.; Lefort, G.; Daoud, S.; Gaillard, D.

    1988-01-01

    Results of CT scan exploration are reported in two cases of subperiosteal chondroma, one in a 4 year old child affecting the anterior tibial tuberosity the other in a 9 year old child involving the upper end of humerus. Data from CT scan imaging were undoubtedly superior to those of conventional radiography and appear to be characteristic of this benign cartilaginous tumor, greatly facilitating correlation between clinical, radiological and pathologic findings. The scanner should allow certain situations to be dedramatized and the surgical attitude adapted when the functional prognosis is involved [fr

  7. Optimized control of X-ray exposure and image noise using a particular multislice CT scanner

    International Nuclear Information System (INIS)

    Yamamoto, Shuji; Suzuki, Masahiro; Kakinuma, Ryutaro; Moriyama, Noriyuki; Koyama, Yoshihiro; Nagasawa, Hirofumi

    2008-01-01

    Patient dose reduction in computed tomography (CT) always results in a trade off between radiation exposure and image quality. There are few reports that estimate the relationship between image quality and X-ray exposure in CT examinations as one optimal index. The purpose of this study was to determine the optimal parameter settings enabling a low radiation exposure without compromising image quality using a particular 4-row multislice CT (MSCT) scanner (Aquilion VZ 4-slice CT scanner, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan). Normalized dose divided by image noise for helical pitches (nDNR: normalized dose to noise ratio) were calculated in consideration of beam collimation and tube current-time product. Optimal tube current-time product was calculated using the nDNR for the helical pitches based on user-defined standards of quality of the CT image. As a result, the nDNR proved to be well-supported to decrease the patient exposure in various exposure conditions of MSCT scans; however, the dose and image noise did not show a linear relation to the helical pitch. In conclusion, nDNR can be applied to patient dose reduction while keeping an acceptable image quality using a particular 4-row MSCT scanner. (author)

  8. SU-F-I-31: Reproducibility of An Automatic Exposure Control Technique in the Low-Dose CT Scan of Cardiac PET/CT Exams

    Energy Technology Data Exchange (ETDEWEB)

    Park, M; Rosica, D; Agarwal, V; Di Carli, M; Dorbala, S [Brigham and Women’s Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Two separate low-dose CT scans are usually performed for attenuation correction of rest and stress N-13 ammonia PET/CT myocardial perfusion imaging (PET/CT). We utilize an automatic exposure control (AEC) technique to reduce CT radiation dose while maintaining perfusion image quality. Our goal is to assess the reproducibility of displayed CT dose index (CTDI) on same-day repeat CT scans (CT1 and CT2). Methods: Retrospectively, we reviewed CT images of PET/CT studies performed on the same day. Low-dose CT utilized AEC technique based on tube current modulation called Smart-mA. The scan parameters were 64 × 0.625mm collimation, 5mm slice thickness, 0.984 pitch, 1-sec rotation time, 120 kVp, and noise index 50 with a range of 10–200 mA. The scan length matched with PET field of view (FOV) with the heart near the middle of axial FOV. We identified the reference slice number (RS) for an anatomical landmark (carina) and used it to estimate axial shift between two CTs. For patient size, we measured an effective diameter on the reference slice. The effect of patient positioning to CTDI was evaluated using the table height. We calculated the absolute percent difference of the CTDI (%diff) for estimation of the reproducibility. Results: The study included 168 adults with an average body-mass index of 31.72 ± 9.10 (kg/m{sup 2}) and effective diameter was 32.72 ± 4.60 cm. The average CTDI was 1.95 ± 1.40 mGy for CT1 and 1.97 ± 1.42mGy for CT2. The mean %diff was 7.8 ± 6.8%. Linear regression analysis showed a significant correlation between the table height and %diff CTDI. (r=0.82, p<0.001) Conclusion: We have shown for the first time in human subjects, using two same-day CT images, that the AEC technique in low-dose CT is reproducible within 10% and significantly depends on the patient centering.

  9. Interobserver variability in visual evaluation of thoracic CT scans and comparison with automatic computer measurements of CT lung density

    DEFF Research Database (Denmark)

    Winkler Wille, Mathilde Marie; Thomsen, Laura Hohwü; Dirksen, Asger

    2012-01-01

    lung density measurements, i.e. densitometry. Methods – In a pilot study 60 CT scans were selected from a sample of 3980 CT scans from The Danish Lung Cancer Screening Trial (DLCST). The amount of emphysema in these scans was scored independently by two observers, who were blinded regarding clinical...... information. The lung was segmented automatically by in-house developed computer software, and the percentage of pixels below -950 HU was used as a surrogate marker for emphysema. The observer variability, as well as the correlation with the lung density measurements, was analysed using Spearman’s rank...... in emphysema grading. However, the agreement with the CT lung density measurement was poor, indicating that the two types of evaluation represent different aspects of emphysema. Most likely, they should be seen as complementary rather than competitive evaluations. Future comparison with physiological tests...

  10. Assessment of pancreatic adenocarcinoma: use of low-dose whole pancreatic CT perfusion and individualized dual-energy CT scanning

    International Nuclear Information System (INIS)

    Li, Hai-ou; Guo, Jun; Li, Xiao; Qi, Yao-dong; Wang, Xi-ming; Xu, Zhuo-dong; Liu, Cheng; Chen, Jiu-hong

    2015-01-01

    The objective of this study was to investigate the value of low-dose whole pancreatic computed tomography (CT) perfusion integrated with individualized dual-energy CT (DECT) scanning in the diagnosis of pancreatic adenocarcinoma. Twenty patients with pancreatic adenocarcinoma underwent pancreatic CT perfusion as well as individualized dual-phase DECT pancreatic scans. Perfusion characteristics of non-tumourous pancreatic parenchyma and pancreatic adenocarcinoma were analysed. Weighted-average 120 kVp images and the optimal monoenergetic images in dual phase were reconstructed and the contrast noise ratio (CNR) of pancreas-to-tumour were compared. There were significant difference on blood flow as well as blood volume between pancreatic adenocarcinoma and the non-tumourous pancreatic parenchyma (P < 0.05), whereas no difference on permeability (P > 0.05). CNRs of pancreas-to-tumour in individualized pancreatic phase were significantly higher than those in venous phase (P < 0.05), and CNRs of optimal monoenergetic images were higher than those on weighted-average 120 kVp images (P < 0.05) in both phase. Total effective radiation dose of CT examination was around 9.32–13.75 mSv. Low-dose whole pancreatic CT perfusion can provide functional information, and the individualized pancreatic phase DECT scan is the optimal method for detecting pancreatic adenocarcinomas. The integration of the two techniques has great value in clinical application.

  11. MRI of patients with cerebral palsy and normal CT scan

    International Nuclear Information System (INIS)

    Bogaert, P. van; Szliwowski, H.B.

    1992-01-01

    Three children with clinical evidence of cerebral palsy (CP) and normal cerebral computed tomography (CT) scans were evaluated by magnetic resonance imaging (MRI) to identify CT-undetectable white matter lesions in the watershed zones of arterial territories. The two patients with spastic diplegia showed bilateral lesions either in the subcortical regions or in the occipital periventricular regions. The patient with congenital hemiplegia exhibited unilateral lesions in the periventricular region. We conclude that MRI is more informative than CT for the evaluation of patients with CP. (orig.)

  12. MRI of patients with cerebral palsy and normal CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Bogaert, P. van; Szliwowski, H.B. (Hopital Erasme, Brussels (Belgium). Dept. of Neurology); Baleriaux, D.; Christophe, C. (Hopital Erasme, Brussels (Belgium). Dept. of Radiology (Neuroradiology))

    1992-02-01

    Three children with clinical evidence of cerebral palsy (CP) and normal cerebral computed tomography (CT) scans were evaluated by magnetic resonance imaging (MRI) to identify CT-undetectable white matter lesions in the watershed zones of arterial territories. The two patients with spastic diplegia showed bilateral lesions either in the subcortical regions or in the occipital periventricular regions. The patient with congenital hemiplegia exhibited unilateral lesions in the periventricular region. We conclude that MRI is more informative than CT for the evaluation of patients with CP. (orig.).

  13. Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

    Directory of Open Access Journals (Sweden)

    Adeleye Bamise

    2017-12-01

    Full Text Available The preference for computed tomography (CT for the clinical assessment of pulmonary tuberculosis (PTB infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05 between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05 and female patients (r2 = 0.989, P < 0.05. The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively. These variations provide an indication that the use of a scanner optimizing protocol is imperative.

  14. Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

    Science.gov (United States)

    Adeleye, Bamise; Chetty, Naven

    2017-12-01

    The preference for computed tomography (CT) for the clinical assessment of pulmonary tuberculosis (PTB) infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05) between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05) and female patients (r2 = 0.989, P < 0.05). The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively). These variations provide an indication that the use of a scanner optimizing protocol is imperative.

  15. Influence of PET/CT-introduction on PET scanning frequency and indications. Results of a multicenter study

    International Nuclear Information System (INIS)

    Stergar, H.; Bockisch, A.; Eschmann, S.M.; Krause, B.J.; Roedel, R.; Tiling, R.; Weckesser, M.

    2007-01-01

    Aim: to evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET. Methods: the study included all examinations performed on stand alone PET- or PET/CT-scanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated. Results: the overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities. Conclusions: the introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry. (orig.)

  16. Body surface area determined by whole-body CT scanning: need for new formulae?

    DEFF Research Database (Denmark)

    Villa, Chiara; Primeau, Charlotte; Hesse, Ulrik

    2017-01-01

    Calculation of the estimated body surface area (BSA) by body height and weight has been a challenge in the past centuries due to lack of a well-documented gold standard. More recently, available techniques such as 3D laser surface scanning and CT scanning may be expected to quantify the BSA...... Mimics software, and BSA values were automatically extracted from the program. They were compared with nine predictive equations from the literature. Remarkably, close correlations (r > 0·90) were found between BSA values from CT scans and those from the predictive formulae. A mean BSA of the 54 cadavers...... equations, with the CT scan determination as gold standard. It is concluded that DuBois and DuBois' equation can be safely used in normal-weight male subjects with high accuracy, but it seems likely that BSA is underestimated in underweight subjects and overestimated in overweight individuals. Creation...

  17. Comparison of helical, maximum intensity projection (MIP), and averaged intensity (AI) 4D CT imaging for stereotactic body radiation therapy (SBRT) planning in lung cancer

    International Nuclear Information System (INIS)

    Bradley, Jeffrey D.; Nofal, Ahmed N.; El Naqa, Issam M.; Lu, Wei; Liu, Jubei; Hubenschmidt, James; Low, Daniel A.; Drzymala, Robert E.; Khullar, Divya

    2006-01-01

    Background and Purpose: To compare helical, MIP and AI 4D CT imaging, for the purpose of determining the best CT-based volume definition method for encompassing the mobile gross tumor volume (mGTV) within the planning target volume (PTV) for stereotactic body radiation therapy (SBRT) in stage I lung cancer. Materials and methods: Twenty patients with medically inoperable peripheral stage I lung cancer were planned for SBRT. Free-breathing helical and 4D image datasets were obtained for each patient. Two composite images, the MIP and AI, were automatically generated from the 4D image datasets. The mGTV contours were delineated for the MIP, AI and helical image datasets for each patient. The volume for each was calculated and compared using analysis of variance and the Wilcoxon rank test. A spatial analysis for comparing center of mass (COM) (i.e. isocenter) coordinates for each imaging method was also performed using multivariate analysis of variance. Results: The MIP-defined mGTVs were significantly larger than both the helical- (p 0.001) and AI-defined mGTVs (p = 0.012). A comparison of COM coordinates demonstrated no significant spatial difference in the x-, y-, and z-coordinates for each tumor as determined by helical, MIP, or AI imaging methods. Conclusions: In order to incorporate the extent of tumor motion from breathing during SBRT, MIP is superior to either helical or AI images for defining the mGTV. The spatial isocenter coordinates for each tumor were not altered significantly by the imaging methods

  18. Normal width of the anterior commissure of true vocal cord in Korea adults measured by helical CT

    International Nuclear Information System (INIS)

    Lim, Woo Young; Lim, Dong Hoon; Moon, Jang Il; Ko, Yong Seok; Byeon, Joo Nam; Oh, Jae Hee

    1998-01-01

    To evaluate the mean width of anterior commissure of true vocal cord in Korean adults by measuring its dimension on spiral CT scans. We reviewed the CT scans of 53 Korean adults(age range, 23-73years; mean age 39.2 years;M:F=3D41:12) without laryngeal disorders. Soiral CT scanning was performed around the anterior commissure with 1mm slice thickness and table incrementation for 15 seconds. The anteroposterior width of the anterior commissure was measured on CT scan where the true vocal cord and arytenoid, cricoid and thyroid cartilages were all present. We determined the mean width of the anterior commissure and whether there was a relationship between age and the width of the anterior commissure. The width of the anterior commissure was between 0.9mm and 2.3mm;mean width was 1.60±0.38mm(mean±SD). Using two SDs above the mean would have defined 2.36mm as the upper limit of normal width. Statistically, no significant correlation existed between the age and the width of the anterior commissure(p>0.05). An awareuess of the normal width range of the anterior commissure in Korean adults evaluated by spiral CT enhances the possibility of early detection of invasion of the anterior commissure by glottic cancer.=20

  19. Emergency medicine summary code for reporting CT scan results: implementation and survey results.

    Science.gov (United States)

    Lam, Joanne; Coughlin, Ryan; Buhl, Luce; Herbst, Meghan; Herbst, Timothy; Martillotti, Jared; Coughlin, Bret

    2018-06-01

    The purpose of the study was to assess the emergency department (ED) providers' interest and satisfaction with ED CT result reporting before and after the implementation of a standardized summary code for all CT scan reporting. A summary code was provided at the end of all CTs ordered through the ED from August to October of 2016. A retrospective review was completed on all studies performed during this period. A pre- and post-survey was given to both ED and radiology providers. A total of 3980 CT scans excluding CTAs were ordered with 2240 CTs dedicated to the head and neck, 1685 CTs dedicated to the torso, and 55 CTs dedicated to the extremities. Approximately 74% CT scans were contrast enhanced. Of the 3980 ED CT examination ordered, 69% had a summary code assigned to it. Fifteen percent of the coded CTs had a critical or diagnostic positive result. The introduction of an ED CT summary code did not show a definitive improvement in communication. However, the ED providers are in consensus that radiology reports are crucial their patients' management. There is slightly increased satisfaction with the providers with less than 5 years of experience with the ED CT codes compared to more seasoned providers. The implementation of a user-friendly summary code may allow better analysis of results, practice improvement, and quality measurements in the future.

  20. Gambaran CT Scan Toraks Sesuai dengan Jenis Sitologi/Histologi pada Pasien Kanker Paru yang Merokok

    Directory of Open Access Journals (Sweden)

    Rosa Tatun

    2016-03-01

    Full Text Available Kanker paru merupakan  penyebab kematian paling banyak akibat keganasan. Kanker paru memberikan gambaran CT scan yang berbeda sesuai dengan jenis sitologi/histologinya. Pemeriksaan CT scan  toraksdengan teknik high resolution computed tomography (HRCT dapat memperlihatkan kelainan kanker parusecara rinci. Penelitian dilakukan di Instalasi Radiologi RSU Persahabatan, Jakarta bekerja sama denganDepartemen Pulmonologi dan Respirasi RSU Persahabatan terhadap 100 sampel yang diperoleh pada bulanNovember 2014 hingga Maret 2015. Berdasarkan jenis sitologi/histologi kanker paru (adenokarsinoma dankarsinoma sel skuamosa/KSS tidak ditemukan  variabel yang bermakna secara statistik  (bentuk, letak, tepispikulasi, tepi lobulasi, nodul satelit. Variabel yang paling banyak ditemukan pada adenokarsinoma maupunKSS adalah bentuk massa, lokasi di sentral dan paru sebelah kanan. Gambaran kanker paru adenokarsinomadan KSS pada pasien merokok paling banyak berupa massa, lokasi di sentral dan lobus kanan paru. Kata kunci: kanker paru, merokok, CT scan toraks   Lung Cancer CT Scan Findings in Smoker Patients Basedon Cytology/Histology Abstract Lung cancer is the leading cause of most deaths due to malignancy. Lung cancer CT scan provides an overview according to the type of cytology / histology. Thorax CT scan with high resolution technique (HRCT may revealdetail lung cancer abnormalities. This study was conducted between Department of Radiology and Departmentof Pulmonology Respiratory, Persahabatan Hospital Jakarta based on 100 samples, November 2014 until March2015. Based on cytological/histological type (adenocarcinoma and squamous cell carcinoma/KSS, it was not found significant meaningfull variables (shape, location, spiculate edge, lobulate edge, satellite nodules. Most commonly variables found in adenocarcinomas and KSS were mass forming, central location, right lung location.Most of adenocarcinoma and SCC in smoked patients were mass forming, central

  1. Direct CT scanning of the lesser pelvis - frontal vs sagittal plane

    International Nuclear Information System (INIS)

    Khadzhigeorgiev, G.; Lichev, A.

    1994-01-01

    Whenever axial scanning alone is used, the anatomical patterns of the true pelvis and the organs contained in it, particularly in women, give rise to diagnostic difficulties during CT assessment of neoplasms originating from these organs. The high demands on precision characterization of the pathological changes in the pelvis minor organs necessitate the obtaining of reliable density and size measurement data, not merely from the axial plane, but from the frontal and sagittal ones as well. The deficient information afforded by secondary reconstruction of the pelvis mind images requires an mandatory evaluation of the potentialities of direct frontal and direct sagittal scanning of the pelvis minor using standard CT equipment. Information yielded by images from direct frontal and direct sagittal pelvis minor scanning as well as diagnostic problems where application of this type of scanning is indicated operational difficulties and their overcoming, are among the issues discussed. 8 figs., 7 refs

  2. Synthetic CT: Simulating low dose single and dual energy protocols from a dual energy scan

    International Nuclear Information System (INIS)

    Wang, Adam S.; Pelc, Norbert J.

    2011-01-01

    Purpose: The choice of CT protocol can greatly impact patient dose and image quality. Since acquiring multiple scans at different techniques on a given patient is undesirable, the ability to predict image quality changes starting from a high quality exam can be quite useful. While existing methods allow one to generate simulated images of lower exposure (mAs) from an acquired CT exam, the authors present and validate a new method called synthetic CT that can generate realistic images of a patient at arbitrary low dose protocols (kVp, mAs, and filtration) for both single and dual energy scans. Methods: The synthetic CT algorithm is derived by carefully ensuring that the expected signal and noise are accurate for the simulated protocol. The method relies on the observation that the material decomposition from a dual energy CT scan allows the transmission of an arbitrary spectrum to be predicted. It requires an initial dual energy scan of the patient to either synthesize raw projections of a single energy scan or synthesize the material decompositions of a dual energy scan. The initial dual energy scan contributes inherent noise to the synthesized projections that must be accounted for before adding more noise to simulate low dose protocols. Therefore, synthetic CT is subject to the constraint that the synthesized data have noise greater than the inherent noise. The authors experimentally validated the synthetic CT algorithm across a range of protocols using a dual energy scan of an acrylic phantom with solutions of different iodine concentrations. An initial 80/140 kVp dual energy scan of the phantom provided the material decomposition necessary to synthesize images at 100 kVp and at 120 kVp, across a range of mAs values. They compared these synthesized single energy scans of the phantom to actual scans at the same protocols. Furthermore, material decompositions of a 100/120 kVp dual energy scan are synthesized by adding correlated noise to the initial material

  3. An assessment of pulmonary emphysema in smokers using CT scan

    International Nuclear Information System (INIS)

    Satoh, Katashi; Kobayashi, Takuya; Misao, Takahiko

    1999-01-01

    We assessed the relationship between PE and smoking in 639 cases (411 males and 228 females with age ranged 21-86 years) who underwent CT scans during the period, from December 1997 to December 1998, under suspicion of respiratory disease on chest radiograph or some respiratory complaints. PE was diagnosed by the existence of low attenuation areas in CT scan and not by pulmonary function tests. CT was performed with 10 mm collimation in a standard algorithm. PE, regardless of the grade, was seen: in 189 out of 348 (54.3%) cases in male smokers and in only 2 out of 63 (3.2%) cases in male non-smokers; and in 5 out of 25 (20.0%) female smokers and in 4 out of 203 (2.0%) female non-smokers. PE was observed in more than half of male smokers. High incidence of PE was also observed in even younger generation, and its severity progresses with advancing age and increasing smoking index. (author)

  4. A New, Simple Method for Estimating Pleural Effusion Size on CT Scans

    Science.gov (United States)

    Moy, Matthew P.; Berko, Netanel S.; Godelman, Alla; Jain, Vineet R.; Haramati, Linda B.

    2013-01-01

    Background: There is no standardized system to grade pleural effusion size on CT scans. A validated, systematic grading system would improve communication of findings and may help determine the need for imaging guidance for thoracentesis. Methods: CT scans of 34 patients demonstrating a wide range of pleural effusion sizes were measured with a volume segmentation tool and reviewed for qualitative and simple quantitative features related to size. A classification rule was developed using the features that best predicted size and distinguished among small, moderate, and large effusions. Inter-reader agreement for effusion size was assessed on the CT scans for three groups of physicians (radiology residents, pulmonologists, and cardiothoracic radiologists) before and after implementation of the classification rule. Results: The CT imaging features found to best classify effusions as small, moderate, or large were anteroposterior (AP) quartile and maximum AP depth measured at the midclavicular line. According to the decision rule, first AP-quartile effusions are small, second AP-quartile effusions are moderate, and third or fourth AP-quartile effusions are large. In borderline cases, AP depth is measured with 3-cm and 10-cm thresholds for the upper limit of small and moderate, respectively. Use of the rule improved interobserver agreement from κ = 0.56 to 0.79 for all physicians, 0.59 to 0.73 for radiology residents, 0.54 to 0.76 for pulmonologists, and 0.74 to 0.85 for cardiothoracic radiologists. Conclusions: A simple, two-step decision rule for sizing pleural effusions on CT scans improves interobserver agreement from moderate to substantial levels. PMID:23632863

  5. Study of CT Scan Flooding System at High Temperature and Pressure

    Science.gov (United States)

    Chen, X. Y.

    2017-12-01

    CT scan flooding experiment can scan micro-pore in different flooding stages by the use of CT scan technology, without changing the external morphology and internal structure of the core, and observe the distribution characterization in pore medium of different flooding fluid under different pressure.thus,it can rebuilt the distribution images of oil-water distribution in different flooding stages. However,under extreme high pressure and temperature conditions,the CT scan system can not meet the requirements. Container of low density materials or thin shell can not resist high pressure,while high density materials or thick shell will cause attenuation and scattering of X-ray. The experiment uses a simple Ct scanning systems.X ray from a point light source passing trough a micro beryllium shell on High pressure stainless steal container,continuously irradiates the core holder that can continuously 360° rotate along the core axis. A rare earth intensifying screen behind the core holder emitting light when irradiated with X ray can show the core X ray section image. An optical camera record the core X ray images through a transparency high pressure glazing that placed on the High pressure stainless steal container.Thus,multiple core X ray section images can reconstruct the 3D core reconstruction after a series of data processing.The experiment shows that both the micro beryllium shell and rare earth intensifying screen can work in high temperature and high pressure environment in the stainless steal container. This way that X-ray passes through a thin layer of micro beryllium shell , not high pressure stainless steal shell,avoid the attenuation and scattering of X-ray from the container shell,while improving the high-pressure experiment requirements.

  6. Dose profile study in head CT scans using radiochromic films

    International Nuclear Information System (INIS)

    Ladino G, A. M.; Prata M, A.

    2016-10-01

    Diagnostic images of computed tomography generate higher doses than other methods of diagnostic radiology using X-ray beam attenuation. Clinical applications of CT have been increased by technological advances, what leads to a wide variety of scanner in the Brazilian technological pool. It has been difficult to implement dose reduction strategies because of the lack of proper guidance on computed tomography examinations. However, CT scanners allow adjusting acquisition parameter according to the patients physical profile and diagnostic application for which the scan is intended. The knowledge of the dose distribution is important because changes in image acquisition parameters may provide dose reduction. In this study, it was used a cylindrical head phantom in PMMA with 5 openings, what allows dose measurement in 5 regions. In a GE CT scanner, Discovery model of 64 channels, the central slice of the head phantom was irradiated and the absorbed doses were measured using a pencil ionization chamber. Radiochromic film strips were placed in the peripheral and in the central region of the head phantom and was performed a scan of 10 cm in the phantom central region. The scan was performed using the head scanning protocol of the radiobiology service, with a voltage of 120 kV. After scanning, the radiochromic film strips were digitalized and their digital images were used to have the dose longitudinal profiles. The dose values recorded have variation in a range of 18.66 to 23.57 mGy. In the results it was compared the dose index values obtained by the pencil chamber measurement to the dose longitudinal profiles recorded by the film strips. (Author)

  7. Dose profile study in head CT scans using radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Ladino G, A. M.; Prata M, A., E-mail: amlgphys@gmail.com [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Diagnostic images of computed tomography generate higher doses than other methods of diagnostic radiology using X-ray beam attenuation. Clinical applications of CT have been increased by technological advances, what leads to a wide variety of scanner in the Brazilian technological pool. It has been difficult to implement dose reduction strategies because of the lack of proper guidance on computed tomography examinations. However, CT scanners allow adjusting acquisition parameter according to the patients physical profile and diagnostic application for which the scan is intended. The knowledge of the dose distribution is important because changes in image acquisition parameters may provide dose reduction. In this study, it was used a cylindrical head phantom in PMMA with 5 openings, what allows dose measurement in 5 regions. In a GE CT scanner, Discovery model of 64 channels, the central slice of the head phantom was irradiated and the absorbed doses were measured using a pencil ionization chamber. Radiochromic film strips were placed in the peripheral and in the central region of the head phantom and was performed a scan of 10 cm in the phantom central region. The scan was performed using the head scanning protocol of the radiobiology service, with a voltage of 120 kV. After scanning, the radiochromic film strips were digitalized and their digital images were used to have the dose longitudinal profiles. The dose values recorded have variation in a range of 18.66 to 23.57 mGy. In the results it was compared the dose index values obtained by the pencil chamber measurement to the dose longitudinal profiles recorded by the film strips. (Author)

  8. Childhood CT scans linked to leukemia and brain cancer later in life

    Science.gov (United States)

    Children and young adults scanned multiple times by computed tomography (CT), a commonly used diagnostic tool, have a small increased risk of leukemia and brain tumors in the decade following their first scan.

  9. Brain atrophy in Huntington's disease: A CT-scan study

    International Nuclear Information System (INIS)

    Starkstein, S.E.; Folstein, S.E.; Brandt, J.; McDonnell, A.; Folstein, M.

    1989-01-01

    CT-scan measurements of cortical and subcortical atrophy were carried out in 34 patients with Huntington's disease (HD). While a significant correlation was observed between parameters of subcortical atrophy (bicaudate ratio, bifrontal ratio and third ventricular ratio) and duration of the disease, there was no significant correlation between these parameters and age. On the other hand, measurements of cortical atrophy (frontal fissure ratio and cortical sulci ratio) correlated significantly with age but not with duration of the disease. When a group of 24 HD patients were compared on CT-scan measurements with a group of 24 age-matched normal controls, significant differences were obtained for all the variables examined, but the bicaudate ratio showed the highest sensitivity and specificity. Even mildly affected patients, with duration of motor symptoms less than 3 years had higher bicaudate ratios than age-matched controls. (orig.)

  10. CT of tracheal agenesis

    International Nuclear Information System (INIS)

    Strouse, Peter J.; Hernandez, Ramiro J.; Newman, Beverley

    2006-01-01

    Tracheal agenesis is a rare and usually lethal anomaly. In the past, opaque contrast medium was injected via the esophagus to demonstrate the anatomy. To demonstrate the utility of helical and multidetector CT in delineating the aberrant anatomy in newborns with tracheal agenesis. Four newborns with tracheal agenesis were identified from three institutions. Imaging studies and medical records were reviewed. Each child was imaged with chest radiography. One child was imaged on a single-detector helical CT scanner and the other three on multidetector scanners. Helical and multidetector CT with 2D and 3D reconstructions clearly delineated the aberrant tracheobronchial and esophageal anatomy in each infant. Minimum intensity projection reformatted CT images were particularly helpful. One infant each had type I and type II tracheal agenesis. Two infants had type III tracheal agenesis. All four infants died. CT is a useful tool for delineating the aberrant anatomy of newborns with tracheal agenesis and thus helps in making rational clinical decisions. (orig.)

  11. Adaptive statistical iterative reconstruction technology in the application of PET/CT whole body scans

    International Nuclear Information System (INIS)

    Xin Jun; Zhao Zhoushe; Li Hong; Lu Zhe; Wu Wenkai; Guo Qiyong

    2013-01-01

    Objective: To improve image quality of low dose CT in whole body PET/CT using adaptive statistical iterative reconstruction (ASiR) technology. Methods: Twice CT scans were performed with GE water model,scan parameters were: 120 kV, 120 and 300 mA respectively. In addition, 30 subjects treated with PET/CT were selected randomly, whole body PET/CT were performed after 18 F-FDG injection of 3.70 MBq/kg, Sharp IR+time of flight + VUE Point HD technology were used for 1.5 min/bed in PET; CT of spiral scan was performed under 120 kV using automatic exposure control technology (30-210 mA, noise index 25). Model and patients whole body CT images were reconstructed with conventional and 40% ASiR methods respectively, and the CT attenuation value and noise index were measured. Results: Research of model and clinical showed that standard deviation of ASiR method in model CT was 33.0% lower than the conventional CT reconstruction method (t =27.76, P<0.01), standard deviation of CT in normal tissues (brain, lung, mediastinum, liver and vertebral body) and lesions (brain, lung, mediastinum, liver and vertebral body) reduced by 21.08% (t =23.35, P<0.01) and 24.43% (t =16.15, P<0.01) respectively, especially for normal liver tissue and liver lesions, standard deviations of CT were reduced by 51.33% (t=34.21, P<0.0) and 49.54% (t=15.21, P<0.01) respectively. Conclusion: ASiR reconstruction method was significantly reduced the noise of low dose CT image and improved the quality of CT image in whole body PET/CT, which seems more suitable for quantitative analysis and clinical applications. (authors)

  12. Coronary artery calcification detected by a mobile helical CT unit in a mass screening. The frequency and relationship to coronary risk factors and coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Itani, Yasutaka; Watanabe, Shigeru; Masuda, Yoshiaki [Chiba Univ. (Japan). School of Medicine; Hanamura, Kazuhisa; Asakura, Kazuhiro; Sone, Shusuke; Sunami, Yuko; Shimura, Akimitsu; Miyamoto, Tadaaki

    2001-06-01

    A strong relationship is known to exist between coronary artery disease (CAD) and coronary artery calcification (CAC) detected by CT. In this study, we investigated the frequency of CAC and the relationship between coronary risk factors, CAD and CAC in a mass screening using a mobile helical CT unit. The total number of participants was 10008 people undergoing a medical examination for lung cancer and tuberculosis using a mobile helical CT unit. We measured the CT density of the coronary artery to detect CAC. The CT density threshold for determining CAC was above +110HU. The frequency of CAC was 16.0% in the overall patient population and significantly higher in males than in females (20.6% vs 10.7%). Frequency increased with age in both genders. Hypertension and diabetes mellitus were significantly related to CAC. Smoking showed a correlation with CAC only in males. A significant relationship was observed between CAD and CAC in males. In particular, the relationship between them was strongest in males under 60 years of age. Furthermore, the odds ratio of CAC in predicting CAD increased with increasing risk factors in both genders. (author)

  13. Evaluation of diagnostic quality in musculoskeletal three-dimensional CT scans

    International Nuclear Information System (INIS)

    Vannier, M.W.; Hildebolt, C.F.; Gilula, L.A.; Sutherland, C.J.; Offutt, C.J.; Drebin, R.; Mantle, M.; Giordono, T.A.

    1988-01-01

    A major application of three-dimensional computed tomography (CT) is in the imaging of the skeleton. Three-dimensional CT has an important role in determining the presence and extent of congenital and acquired orthopedic abnormalities. The objective of this study was to compare the diagnostic sensitivity and specificity of three-dimensional CT, planar CT, and plain radiography in the detection and characterization of orthopedic abnormalities. Three-dimensional CT scan reconstructions were obtained by two methods, surface reconstruction and volumetric techniques. Seventy patients were imaged with CT, three-dimensional CT, and plain radiography. The consensus opinion of experts with access to all images plus clinical history, surgical findings, and follow-up findings were taken as truth. Expert radiologists read these cases in a blinded fashion. The results were compared using receiver operating characteristic (ROC) analysis. The diagnostic value of each three-dimensional reconstruction method and the parameters used to perform the reconstructions were evaluated

  14. Virtual CT-colonoscopy. Examination technique, limitations, and prospects

    International Nuclear Information System (INIS)

    Springer, P.; Dessl, A.; Giacomuzzi, S.M.; Stoehr, B.; Stoeger, A.; Bodner, G.; Buchberger, W.

    1997-01-01

    Virtual CT-colonoscopy is a post-processing method which allows for reconstruction of inner bowel surface structures from helical CT datasets. The reconstructed images simulate the views which are known from fiberoptic endoscopy. Since colorectal cancer is the second main cause of death in USA and Europe today and since recent screening recommendations are often ignored by the public, a non-invasive or minimal-invasive procedure for colonic evaluation would offer some benefits. Virtual CT-colonoscopy generally involves three essential steps: patient preparation with cleansing of the bowel and administration of an air enema, helical CT-examination by using appropriate scan parameters, and interactive 3D rendering of the volume dataset. Although recent studies have demonstrated that polypoid lesions of about 5 mm size are well detectable and although virtual colonoscopy offers many advantages over fiberoptic endoscopy, some technical and clinical limitations must still be noted. Thus, the current inability of virtual colonoscopy to provide texture and color leads to problems in identifying flat lesions; the presence of retained or adherent fecal matter may result to false positive diagnosis and collapsed segments of bowel may cause problems as they cannot subsequently be evaluated during image reconstruction. Virtual endoscopy is still in its infancy and further technical and clinical development are necessary. (orig./AJ) [de

  15. Pathophysiological study of experimental hydrocephalus with computed tomography (CT) scan

    International Nuclear Information System (INIS)

    Murata, Takaho

    1980-01-01

    In order to investigate the pathophysiological changes during a development of hydrocephalus, the observations employing computed tomography (CT) scans and monitorings of intracranial epidural pressure (EDP) were performed in a series of kaolin-induced canine hydrocephalus. According to ''volume index'' of ventricles which was calculated from printed-out CT numbers, great individual variations were recognized in the degree of a ventricular enlargement as well as the rate of EDP. They are thought to be due to the difference in types of hydrocephalus, which have been induced by a discrepancy in the site and degree of an obstruction caused by kaolin. Periventricular lucency (PVL) of various degrees were also detected on CT scans of experimental hydrocephalus. It was always marked in the superolateral angle of frontal horn of the lateral ventricles, and differed in degree from severe to mild. PVLs were distinct in the acute stage with high EDP, and gradually became indistinct and had a tendency to disappear thereafter along with decreased EDP. They immediately disappeared after shunting operation. The pathogenesis of PVL was investigated with histological examinations, as well as by using contrast enhancement, Metrizamide ventriculography, the analysis of linear density profiles, and the measurement of regional cerebral blood flow (rCBF). Consequently, PVLs in hydrocephalus are considered to represent an acute edema or a chronic CSF retention in the periventricular white matter caused by increase of water content. In other words, they are regarded as a sign of present or preceding intraventricular hypertension on CT scan, and may become a clinical indication for shunting operation. (author)

  16. Malignant pleural mesothelioma with heterologous osteoblastic differentiation: case report of the characteristic CT and bone scan findings

    International Nuclear Information System (INIS)

    Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong

    2008-01-01

    Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications

  17. Malignant pleural mesothelioma with heterologous osteoblastic differentiation: case report of the characteristic CT and bone scan findings

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications.

  18. Advantage of CT scan in muscular pathology. Personal cases and review of the literature

    International Nuclear Information System (INIS)

    Laroche, M.; Rousseau, H.; Mazieres, B.; Bonafe, A.; Joffre, F.; Arlet, J.

    1989-01-01

    The advantage of CT scans in muscular pathology is studied. The scan, in addition to the diagnosis of tumors and muscular abscesses, permits to differentiate primary myopathies from neurogenic atrophies: in the course of myopathies, the muscle volume is preserved and they appear as a hypodensity; in neurogenic atrophies, the muscle volume is reduced with preserved density. The CT scan permits to determine the extension of these lesions. In the course of polymyositis, certain forms of rheumatid arthritis, the scan discloses a trabecular and 'worm-eaten' aspect of the muscles. This is also observed after long-term steroid therapy and other endocrine diseases (hyperthyroidism, osteomalacia) indicating an infra-clinical myopathy. In vertebral osteoporosis with fractures and patients with chronic lumbalgia, very ofter, an atrophy of the spinal muscle is observed. Finally, in the course of acquired kyphosis of the adult patient (camptocormia), the CT scan suggest an isolated myopathy, with late manifestations, of the paravertebral muscles [fr

  19. Advantage of CT scan in muscular pathology. Personal cases and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, M.; Rousseau, H.; Mazieres, B.; Bonafe, A.; Joffre, F.; Arlet, J.

    1989-05-01

    The advantage of CT scans in muscular pathology is studied. The scan, in addition to the diagnosis of tumors and muscular abscesses, permits to differentiate primary myopathies from neurogenic atrophies: in the course of myopathies, the muscle volume is preserved and they appear as a hypodensity; in neurogenic atrophies, the muscle volume is reduced with preserved density. The CT scan permits to determine the extension of these lesions. In the course of polymyositis, certain forms of rheumatid arthritis, the scan discloses a trabecular and 'worm-eaten' aspect of the muscles. This is also observed after long-term steroid therapy and other endocrine diseases (hyperthyroidism, osteomalacia) indicating an infra-clinical myopathy. In vertebral osteoporosis with fractures and patients with chronic lumbalgia, very ofter, an atrophy of the spinal muscle is observed. Finally, in the course of acquired kyphosis of the adult patient (camptocormia), the CT scan suggest an isolated myopathy, with late manifestations, of the paravertebral muscles.

  20. Multislice helical CT analysis of small-sized airway wall thickness in smokers and patients with bronchial asthma

    International Nuclear Information System (INIS)

    Sekimura, Kenshi; Ito, Harumasa; Nakamura, Yutaka; Kobayashi, Hitoshi; Oikawa, Hirobumi; Inoue, Hiroshi; Ehara, Shigeru; Yamauchi, Kohei

    2010-01-01

    There is accumulating evidence that airway remodeling, which contributes to airway narrowing, plays a role in the pathogenesis of bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD). Development of the multislice helical CT (MSCT) with improved spatial resolution has made it possible to obtain more precise imaging of small-sized airways. Small-sized airway wall-thickness was measured using the MSCT scan to analyze small-sized airways of smokers and BA patients, and examine the effects of a β 2 agonists on small-sized airway wall-thickness of BA patients. Thirty-six non-asthmatics who participated in the Health Check Program of Iwate Medical University and 25 patients with asthma were recruited. Amongst the 36 non-asthmatics were 20 healthy never-smokers and 15 smokers. The other 25 asthmatics were recruited from the outpatient clinic at Iwate Medical University. MSCT was performed and the right B10 bronchus was chosen for dimensional analysis. Airway wall thickness was expressed as a percentage of wall area (WA%). WA% of the 7 asthmatics before and 30 mim after procaterol (20μg) inspiration were compared. Small-sized airway wall thickness was significantly increased in smokers and patients with asthma compared to healthy never-smokers, when determined by MSCT. Both %V 50 and %V 25 had significant negative correlations with WA% among the healthy never-smokers and smoker population. Procaterol inspiration reduced WA% in the small airway of patients with asthma. Increase of small-sized airway thickness measured by MSCT scan may reflect peripheral obstructive lesions of smokers and BA patients. (author)

  1. Low-Dose and Standard-Dose Unenhanced Helical Computed Tomography for the Assessment of Acute Renal Colic: Prospective Comparative Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Soo; Hwang, Im Kyung; Choi, Yo Won; Namkung, Sook; Kim, Heung Cheol; Hwang, Woo Cheol; Choi, Kuk Myung; Park, Ji Kang; Han, Tae Il; Kang, Weechang [Cheju National Univ. College of Medicine, Jeju (Korea, Republic of). Dept. of Diagnostic Radiology

    2005-11-01

    Purpose: To compare the efficacy of low-dose and standard-dose computed tomography (CT) for the diagnosis of ureteral stones. Material and Methods: Unenhanced helical CT was performed with both a standard dose (260 mAs, pitch 1.5) and a low dose (50 mAs, pitch 1.5) in 121 patients suspected of having acute renal colic. The two studies were prospectively and independently interpreted for the presence and location of ureteral stones, abnormalities unrelated to stone disease, identification of secondary signs, i.e. hydronephrosis and perinephric stranding, and tissue rim sign. The standard-dose CT images were interpreted by one reviewer and the low-dose CT images independently by two reviewers unaware of the standard-dose CT findings. The findings of the standard and low-dose CT scans were compared with the exact McNemar test. Interobserver agreements were assessed with kappa analysis. The effective radiation doses resulting from two different protocols were calculated by means of commercially available software to which the Monte-Carlo phantom model was given. Results: The sensitivity, specificity, and accuracy of standard-dose CT for detecting ureteral stones were 99%, 93%, and 98%, respectively, whereas for the two reviewers the sensitivity of low-dose CT was 93% and 95%, specificity 86%, and accuracy 92% and 94%. We found no significant differences between standard-dose and low-dose CT in the sensitivity and specificity for diagnosing ureter stones ( P >0.05 for both). However, the sensitivity of low-dose CT for detection of 19 stones less than or equal to 2 mm in diameter was 79% and 68%, respectively, for the two reviewers. Low-dose CT was comparable to standard-dose CT in visualizing hydronephrosis and the tissue rim sign. Perinephric stranding was far less clear on low-dose CT. Low-dose CT had the same diagnostic performance as standard-dose CT in diagnosing alternative diseases. Interobserver agreement between the two low-dose CT reviewers in the diagnosis of

  2. Preliminary study of the scan-delay-time during the combined examation of CT perfusion and CT angiography after contrast media administration in cerebral and cervical CT angiography

    International Nuclear Information System (INIS)

    Cai Wu; Gong Jianping; Zhu Jiangtao; Qiao Fang; Chen Guangqiang; Zhang Bo; Yi Bixing; Qian Minghui

    2010-01-01

    Objective: To discuss the feasibility of the time to peak of cerebral CT perfusion (CTP) in predicting the scan-delay-time after contrast media administration in cerebral and cervical CT angiography (CTA). Methods: Retrospective Analysis was performed in eighty patients who had been examined with cerebral and cervical CTA, they were divided randomly into two groups. Group A:40 patients were performed by the method of experience of 20 seconds as scan-delay-time. Group B:the other 40 patients were examined with the combination scanning technology of CTP-CTA. They were all measured with enhancement value of CT in the M1 segment of left middle cerebral artery, superior sagittal sinus , left common carotid artery adjacent to the fourth cervical vertebrace and internal jugular vein, and then calculate the difference between the arterys and the veins in the same layer. Statistical significance was determined with t test. Results: (1)The enhancement value of CT in the cerebral and cervical artery vessels and the resolving power between the arterys and the veins in the same layer of group B were higher than that in group A. (2) Group B whose cerebral and cervical artery vessels rescontructed from the raw CT data set showed clearly; There were an advance in 3 cases (7.5%), a delay in 5 cases (12.5%) in group A whose cerebral and cervical artery vessels rescontructed from the raw CT data set didn't show clearly.Conclusion It's a satisfactory method based on successful cerebral and cervical CTA study to take the time to peak in CT perfusion as the scan-delay-time during the combined examination of CTP and CTA with 64-detector spiral CT. (authors)

  3. Two methods for isolating the lung area of a CT scan for density information

    International Nuclear Information System (INIS)

    Hedlund, L.W.; Anderson, R.F.; Goulding, P.L.; Beck, J.W.; Effmann, E.L.; Putman, C.E.

    1982-01-01

    Extracting density information from irregularly shaped tissue areas of CT scans requires automated methods when many scans are involved. We describe two computer methods that automatically isolate the lung area of a CT scan. Each starts from a single, operator specified point in the lung. The first method follows the steep density gradient boundary between lung and adjacent tissues; this tracking method is useful for estimating the overall density and total area of lung in a scan because all pixels within the lung area are available for statistical sampling. The second method finds all contiguous pixels of lung that are within the CT number range of air to water and are not a part of strong density gradient edges; this method is useful for estimating density and area of the lung parenchyma. Structures within the lung area that are surrounded by strong density gradient edges, such as large blood vessels, airways and nodules, are excluded from the lung sample while lung areas with diffuse borders, such as an area of mild or moderate edema, are retained. Both methods were tested on scans from an animal model of pulmonary edema and were found to be effective in isolating normal and diseased lungs. These methods are also suitable for isolating other organ areas of CT scans that are bounded by density gradient edges

  4. Physics properties of non-helical scan using 320-row multi detector computed tomography

    International Nuclear Information System (INIS)

    Urikura, Atsushi; Nakaya, Yoshihiro; Kawatani, Keisuke; Kawashima, Ippei; Goto, Hironori; Ichikawa, Katsuhiro

    2012-01-01

    Recently, clinical applications utilizing 320-row multi detector computed tomography (320MDCT) have increased, and the physical image properties of 320MDCT have been more concerned. We evaluated the spatial resolution in scan plane and z-direction, image noise and low-contrast sensitivity of non-helical mode (320NH), 640 slices mode by a double slice reconstruction technology (640DS), and 64-row helical mode (64HE) by using a 320MDCT. The spatial resolution in z-direction was evaluated by the section sensitivity profile (SSP) measurement with the micro coin phantom and the contrast transfer ratio (CTR) with the 0.5-mm comb phantom. The in-plane spatial resolution of 320NH was uniform over all the slice positions. The spatial resolution in z-direction decreased from the cathode side toward the anode side. The image noise of the anode side was higher than that of the cathode side. The contrast to noise ratio as index of the low contrast sensitivity was uniform over all the slice position. The CTR of 320NH fluctuated in the z-position, and the fluctuation was improved by 640DS except for the center of rotation. (author)

  5. Repeat CT-scan assessment of lymph node motion in locally advanced cervical cancer patients

    International Nuclear Information System (INIS)

    Bondar, Luiza; Velema, Laura; Mens, Jan Willem; Heijmen, Ben; Hoogeman, Mischa; Zwijnenburg, Ellen

    2014-01-01

    In cervical cancer patients the nodal clinical target volume (CTV, defined using the major pelvic blood vessels and enlarged lymph nodes) is assumed to move synchronously with the bony anatomy. The aim of this study was to verify this assumption by investigating the motion of the major pelvic blood vessels and enlarged lymph nodes visible in CT scans. For 13 patients treated in prone position, four variable bladder-filling CT scans per patient, acquired at planning and after 40 Gy, were selected from an available dataset of 9-10 CT scans. The bladder, rectum, and the nodal-vessels structure containing the iliac vessels and all visible enlarged nodes were delineated in each selected CT scan. Two online patient setup correction protocols were simulated. The first corrected bony anatomy translations and the second corrected translations and rotations. The efficacy of each correction was calculated as the overlap between the nodal-vessels structure in the reference and repeat CT scans. The motion magnitude between delineated structures was quantified using nonrigid registration. Translational corrections resulted in an average overlap of 58 ± 13% and in a range of motion between 9.9 and 27.3 mm. Translational and rotational corrections significantly improved the overlap (64 ± 13%, p value = 0.007) and moderately reduced the range of motion to 7.6-23.8 mm (p value = 0.03). Bladder filling changes significantly correlated with the nodal-vessels motion (p [de

  6. Anterior glenoid rim fracture: the value of helical CT with threedimensional reconstruction and electronic humeral disarticulation

    Directory of Open Access Journals (Sweden)

    Heverton César de Oliveira

    2003-06-01

    Full Text Available Objectives: To show a new three-dimensional reconstructiontechnique based on helical computed tomography images withelectronic humeral disarticulation in anterior glenoid rim fractures,correlating the anatomic specimen with simulation of an anteriorglenoid rim fracture, as well as evaluating the extension of thefracture, the bone fragment position and distance in relation to theglenoid cavity in six patients. Methods: One scapula and onehumerus with no signs of fracture or congenital malformationswere placed in anatomical position using an adhesive tape aftersimulating an anterior glenoid rim fracture made by an osteotome.Helical CT imaging was acquired and three-dimensionalreconstructions were made based on these images, with andwithout electronic humeral disarticulation. The bone fragment waslocated, measured and its position in relation to the glenoid cavitywas assessed. Six patients with anterior glenoid rim fracture weresubmitted to CT of the shoulder using the same parameters asthose applied to the anatomic specimen. Results: In the anatomicspecimen and in all six patients the bone fragment was clearlydemonstrated; bone fragment measurements in the anatomicspecimen and in three-dimensional reconstructions wereequivalent. The fragment was better demonstrated in the imagestaken with electronic humeral disarticulation, particularly in thefrontal view of the glenoid cavity as observed in all six patients.Conclusion: We concluded that our experiment with the anatomicspecimen and the study of six patients allow us to state that thistechnique is safe and accurate to demonstrate the extension, sizeand location of the bone fragment in anterior glenoid rim fractures,and it provides essential elements for therapeutic planning.

  7. Examination of CT-AEC when the positioning changes after planning of CT scanning

    International Nuclear Information System (INIS)

    Esaki, Tooru; Yamazaki, Shoichi

    2009-01-01

    CT-automatic exposure control (AEC) controls tube current collecting information of the subject from positioning shooting. Because of this, we consider that CT-AEC does not get to operate properly if the body position of the test subject changes after the positioning shooting. However, we often experience in body positions of test subjects after the positioning shooting. In cases like this, we measured by using a phantom again to see how they affect the tube current value and standard deviation (SD) value comparing them to the normal scan where a body position does not change. As a result of the measurement, there was an impact on CT-AEC that optimization of tube current becomes insufficient if the body position of a test subject changes. As the image quality is deteriorated and radiation exposure increases because of this, taking positioning shooting again is required on the part of users and it's desirable on the part of manufacturers to develop CT-AEC that can be controlled with high accuracy. (author)

  8. Imaging Features of Helical Computed Tomography Suggesting Advanced Urothelial Carcinoma Arising from the Pelvocalyceal System

    International Nuclear Information System (INIS)

    Kwak, Kyung Won; Park, Byung Kwan; Kim, Chan Kyo; Lee, Hyun Moo; Choi, Han Y ong

    2008-01-01

    Background: Urothelial carcinoma is the most common malignant tumor arising from the pelvocalyceal system. Helical computed tomography (CT) is probably the best preoperative-stage modality for the determination of treatment plan and prognosis. Purpose: To obtain helical CT imaging features suggesting advanced pelvocalyceal urothelial carcinoma. Material and Methods: Preoperative CT images in 44 patients with pelvocalyceal urothelial carcinoma were retrospectively reviewed and correlated with the pathological examination to determine imaging features suggesting stage III or IV of the disease. Results: Pathological stages revealed stage I in 16, stage II in three, stage III in 17, and stage IV in eight patients. Seven patients had metastatic lymph nodes. CT imaging showed that renal parenchymal invasion, sinus fat invasion, and lymph node metastasis were highly suggestive of advanced urothelial cell carcinoma (P<0.05). Helical CT sensitivity, specificity, and accuracy for advanced pelvocalyceal urothelial carcinoma were 76% (19/25), 84% (16/19), and 80% (35/44), respectively. Conclusion: Preoperative helical CT may suggest imaging features of advanced urothelial carcinoma, influencing treatment plan and patient prognosis, even though its accuracy is not so high

  9. Eye lens radiation exposure and repeated head CT scans: A problem to keep in mind

    International Nuclear Information System (INIS)

    Michel, Morgane; Jacob, Sophie; Roger, Gilles; Pelosse, Béatrice; Laurier, Dominique; Le Pointe, Hubert Ducou; Bernier, Marie-Odile

    2012-01-01

    Objectives: The deterministic character of radiation-induced cataract is being called into question, raising the possibility of a risk in patients, especially children, exposed to ionizing radiation in case of repeated head CT-scans. This study aims to estimate the eye lens doses of a pediatric population exposed to repeated head CTs and to assess the feasibility of an epidemiological study. Methods: Children treated for a cholesteatoma, who had had at least one CT-scan of the middle ear before their tenth birthday, were included. Radiation exposure has been assessed from medical records and telephone interviews. Results: Out of the 39 subjects contacted, 32 accepted to participate. A total of 76 CT-scans were retrieved from medical records. At the time of the interview (mean age: 16 years), the mean number of CT per child was 3. Cumulative mean effective and eye lens doses were 1.7 mSv and 168 mGy, respectively. Conclusion: A relatively high lens radiation dose was observed in children exposed to repeated CT-scans. Due to that exposure and despite the difficulties met when trying to reach patients’ families, a large scale epidemiological study should be performed in order to assess the risk of radiation-induced cataracts associated with repeated head CT.

  10. Study on CT scanning technique of inferior horn of lateral ventricle

    International Nuclear Information System (INIS)

    Kakoi, Iwao; Okubo, Mitsuo; Nakamura, Sumio; Yoshinaga, Toshihiko; Shimono, Tetsuo

    1984-01-01

    It is said that temporal lobe epilepsy (TLE), one of the incurable epilepsies, results from the lesions of various structrues located in the medial and deep portion of the temporal lobe such as the hippocampus and amygdaloid nucleus. Routine CT scanning techniques cannot adequately delineate these structures in the assessment of TLE. The anatomical relationship between these medial temporal structures and the inferior horn of lateral ventricle which is lateral to them and easily identified by CT lead us to believe that the sections through the longitudinal plane of the inferior horn may clearly delineate them. The present experimental study was undertaken to develop the CT scan technique of the inferior horn of lateral ventricle, which results in the clear delineation of the region of the hippocampus and amygdaloid nucleus. As a result, A total of the 3-4 reversed axial 5 mm-thick section centered at 2.5 cm cephalad to the roof of the external auditory canal at a reversed 25 0 angle to ABL are adequate to delineate the inferior horn and the medial temporal structures. This scan technique is considered to be useful in the assessment of TLE. (author)

  11. Intrathoracic kidney. Diagnostic value of CT scan imaging

    International Nuclear Information System (INIS)

    Baillet, A.M.; Escure, M.N.

    1988-01-01

    Two cases are reported of an ectopic right kidney that was partially intrathoracic in position. Diagnosis was simple from CT scan imaging appearances, the examination being performed to investigate an intrathoracic mass. Images showed a tissular mass within a fatty zone in sections without contrast and the typical appearance of the kidney on sections with contrast [fr

  12. Correlation between image quality of CT scan and amount of intravenous contrast media

    International Nuclear Information System (INIS)

    Yoon, Dae Young; Choi, Dae Seob; Kim, Seung Hyup; Han, Joon Koo; Choi, Byung Ihn; Im, Jung Gi; Han, Moon Hee; Chang, Kee Hyun; Kim, Jong Hyo; Han, Man Chung

    1993-01-01

    A blind, comparative clinical study was performed prospectively to examine the correlation between image quality of CT scan in terms of contrast enhancement effect and amount of intravenous contrast media. A total of 357 patients were randomized into two groups. Ionic high-osmolality contrast media (68% meglumine ioglicate) was administered intravenously as 100 ml bolus in one group and as 50 ml bolus in the other group. Statistically significant differences of image quality were found in CT scans of the brain, head and neck, chest and abdomen (p 0.05). We suggest that amount of contrast media may be reduced in pelvis CT without significant degradation of image quality

  13. Study of CT head scans using different voltages: image quality evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco de Freitas C, I.; Prata M, A. [Centro Federal de Educacao Tecnologica de Minas Gerais, Centro de Engenharia Biomedica, Av. Amazonas 5253, 30421-169 Nova Suica, Belo Horizonte, Minas Gerais (Brazil); Alonso, T. C. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil); Santana, P., E-mail: iarapfcorrea@gmail.com [Universidade Federal de Minas Gerais, Departamento de Anatomia e Imagem, Av. Prof. Alfredo Balena 190, 30130-100 Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Computed tomography (CT) was introduced to medical practice in 1972. It generates images recognized by high diagnostic potential. CT allows investigation of structures in the human body inaccessible by conventional image methods, replacing invasive methods in many cases. Noise is a kind of variation of brightness observed on CT images, and it is inherent to this method. The magnitude of the noise is determined by the standard deviation of CT numbers of a region of interest in a homogeneous material. The aim of this study is to analyze the noise in head CT images generated by different acquisition protocols using four voltage values. Five different scans were performed using a female Alderson phantom and their images were analyzed with the RadiAnt software. With the average HU values and standard deviation of each scan, the values of noise were calculated in some region of interest. The obtained noise values were compared and it was observed that the 140 kV voltage promotes the in the lower noise in the image, resulting in better image quality. The results also show that the parameters, such as voltage and current, can be adjusted so that the noise can be decreased. Thus, acquisition protocols may be adapted to produce images with diagnostic quality and lower doses in patient. (Author)

  14. Study of CT head scans using different voltages: image quality evaluation

    International Nuclear Information System (INIS)

    Pacheco de Freitas C, I.; Prata M, A.; Alonso, T. C.; Santana, P.

    2016-10-01

    Computed tomography (CT) was introduced to medical practice in 1972. It generates images recognized by high diagnostic potential. CT allows investigation of structures in the human body inaccessible by conventional image methods, replacing invasive methods in many cases. Noise is a kind of variation of brightness observed on CT images, and it is inherent to this method. The magnitude of the noise is determined by the standard deviation of CT numbers of a region of interest in a homogeneous material. The aim of this study is to analyze the noise in head CT images generated by different acquisition protocols using four voltage values. Five different scans were performed using a female Alderson phantom and their images were analyzed with the RadiAnt software. With the average HU values and standard deviation of each scan, the values of noise were calculated in some region of interest. The obtained noise values were compared and it was observed that the 140 kV voltage promotes the in the lower noise in the image, resulting in better image quality. The results also show that the parameters, such as voltage and current, can be adjusted so that the noise can be decreased. Thus, acquisition protocols may be adapted to produce images with diagnostic quality and lower doses in patient. (Author)

  15. Conformal avoidance helical tomotherapy for dogs with nasopharyngeal tumors

    International Nuclear Information System (INIS)

    Welsh, J.S.; Turek, M.; Mackie, T.R.; Miller, P.; Mehta, M.P.; Forrest, L.J.

    2003-01-01

    Helical tomotherapy provides a unique means of delivering intensity-modulated radiation therapy (IMRT) using a novel treatment unit, which merges features of a linear accelerator with a helical CT scanner. Thanks to the CT imaging capacity, targeted regions can be visualized prior to, during, or immediately after each treatment. Such image-guidance through megavoltage CT will allow the realization and refinement of the concept of adaptive radiotherapy - the reconstruction of the actually delivered daily dose (as opposed to planned dose) accompanied by prescription adjustments when appropriate. In addition to this unique feature, helical tomotherapy promises further improvements in the specific avoidance of critical normal structures, i.e. conformal avoidance, the counterpart of conformal therapy. The first definitive treatment protocol using helical tomotherapy is presently underway for dogs with nasopharyngeal tumors. In general, such tumors can be treated with conventional external beam radiation therapy but at the cost of severe ocular toxicity due to the anatomy of the canine head. These are readily measurable toxicities and are almost universal in incidence; therefore, the canine nasopharyngeal tumor presents an ideal model to assess the ability to conformally avoid critical structures. It is hoped that conformal avoidance helical tomotherapy will improve tumor control via dose-escalation while reducing ocular toxicity in these veterinary patients. A total of 10 fractions are scheduled for these patients; the first 3 dogs have all received at least 7 fractions delivered via helical tomotherapy. Although preliminary, the first 3 dogs treated have not shown any evidence of ocular toxicity in this ongoing study

  16. Reference dosimetry for CT in the UK

    International Nuclear Information System (INIS)

    Shrimpton, P.C.; Wall, B.F.

    2001-01-01

    Computed tomography is firmly established as a major source of population exposure from diagnostic x-ray examinations and thus a particular focus for radiological protection initiatives. The concept of reference doses is widely recognised as a useful and practical tool for promoting improvements in the optimisation of protection for patients undergoing radiological examinations. National diagnostic reference levels (DRLs) have already been successfully applied in the UK for some conventional x-ray examinations within a framework for advice on patient protection. This approach is being extended to include CT, utilising the robust methodology for reference dosimetry that has been developed by the European Commission (EC) for the particular conditions of exposure in CT. This is based on the dosimetric concepts of weighted computed tomography dose index (CTDI w ) per slice in serial scanning or per rotation in helical scanning, and dose-length product (DLP) per complete examination. Notwithstanding some initial values proposed by the EC, specific national DRLs for CT practice in the UK will be established on the basis of widescale national survey data. (author)

  17. Virtual planning of dental implant placement using CT double scan-technique - own experience

    International Nuclear Information System (INIS)

    Wojciechowski, W.; Urbanik, A.; Kownacki, P.; Kownacki, S.

    2007-01-01

    The correctness of CT performed with the use of a double-scan technique is the basis for achieving proper quality of 3D reconstructions of the maxilla or mandible and subsequent virtual planning of dental implant placement. The aim of this study was the presentation of the methodology of computed tomography scanning and own experience with the use of the double-scan technique. The study group included 26 individuals who underwent MDCT with a double-scan technique using a MDCT scanner SOMATOM Sensation (Siemens, Germany). The parameters of the examination: slice-collimation 10 x 0.75 mm, slice-thickness 0.75 mm. The first CT scan in the procedure was the scan of the patient wearing a radiological prosthesis and occlusal index, which was followed by a separate scan of the radiological prosthesis. These two CT scans were copied and transferred to PC with Procera Software program (Nobel Biocare, Sweden) where dental implant placement was virtually planned. In all 26 patients, precise three-dimensional reconstructions of the anatomical structure were obtained. In 11 patients, on the basis of the virtual planning, the implant placement was performed, 5 patients were referred to preparatory procedures, that is, restoration of the alveolar process, otolaryngological treatment of the maxillary sinuses. The remaining 10 patients did not qualify to the procedure because of unfavorable anatomical ideation's. Correct computed tomography with double-scan technique enables virtual planning of dental implant placement, on the basis of which the real procedure of implantation can be performed. (author)

  18. CT scanning in Australia: a report by the National Health Technology Advisory Panel

    International Nuclear Information System (INIS)

    1988-06-01

    An overview of trends in the usage of CT scanning in Australia is given and the areas of benefit and uncertainty associated with this technology are outlined. Numbers and distribution of CT units, costs of CT services, clinical applications, safety aspects and the effects of new developments are discussed. 54 refs., 5 figs., 18 tabs

  19. Application of low-dose radiation protocols in survey CT scans

    International Nuclear Information System (INIS)

    Fu Qiang; Liu Ting; Lu Tao; Xu Ke; Zhang Lin

    2009-01-01

    Objective: To characterize the protocols with low-dose radiation in survey CT scans for localization. Methods: Eighty standard adult patients, head and body phantoms were recruited. Default protocols provided by operator's manual setting were that all the tube voltage for head, chest, abdomen and lumbar was 120 kV; the tube currents were 20,10,20 and 40 mA, respectively. Values of kV and mA in the low-dose experiments were optimized according to the device options. For chest and abdomen, the tube position were compared between default (0 degree) and 180 degree. Phantoms were scanned with above protocols, and the radiation doses were measured respectively. Paired t-test were used for comparisons of standard deviation in CT value, noise and exposure surface dose (ESD) between group with default protocols and group with optimized protocols. Results: The optimized protocols in low-dose CT survey scans were 80 kV, 10 mA for head, 80 kV, 10 mA for chest, 80 kV, 10 mA for abdomen and 100 kV, 10 mA for lumbar. The values of ESD for phantom scan in default and optimized protocols were 0.38 mGy/0.16 mGy in head, 0.30 mGy/0.20 mGy in chest, 0.74 mGy/0.30 mGy in abdomen and 0.81 mGy/0.44 mGy in lumbar, respectively. Compared with default protocols, the optimized protocols reduced the radiation doses 59%, 33%, 59% and 46% in head, chest, abdomen and lumbar. When tube position changed from 0 degree to 180 degree, the ESD were 0.24 mGy/0.20 mGy for chest; 0.37 mGy/0.30 mGy for abdomen, and the radiation doses were reduced 20% and 17%. Conclusion: A certain amount of image noise is increased in low-dose protocols, but image quality is still acceptable without problem in CT localization. The reduction of radiation dose and the radiation harm to patients are the superiority. (authors)

  20. Posterior Urethra Rupture: Contrast-Enhanced Computed Tomography Scan and Urethrocystography Demonstrations

    Directory of Open Access Journals (Sweden)

    Wojciech Marks

    2012-01-01

    Full Text Available In the follow-up study of patients with pelvic fractures, rupture of the posterior urethra is registered in 3–25% of cases (Koraitim et al., 1996. The diagnostic gold standard for the assessment of hemodynamically stable trauma patients is contrast-enhanced CT scan, especially helical CT. Nevertheless, simultaneous suprapubic cystography and ascending urethrograms (the so-called up-and-downogram are the investigation of choice in assessing the site, severity, and length of urethral injuries. (Carlin and Resnick, 1995 This paper discusses the evaluation and diagnosis of urethral injury in multiple-trauma patient.

  1. Fibroelastic pseudotumor elastofibroma dorsi detected by 18F-FDG PET/CT scan and by postherapy radioiodine SPECT/CT.

    Science.gov (United States)

    Oporto, M; Cepa, F; Orta, N; Rubí, S; Navalón, H; Peña, C

    Radioiodine uptake in the thyroid tissue, metastasis of differentiated thyroid cancer (DTC), and in other tissues, depends on the expression of sodium-iodide symporter (NIS). Vascular permeability, effusions, inflammation, and other mechanisms may also play a role in the accumulation of radioactive iodine. A 63-year-old woman underwent radioiodine therapy, as well as a post-therapy whole-body scan, as she was suspected of having lung metastasis from thyroid carcinoma. The scan not only showed uptake at the lung metastasis but also a faint diffuse bilateral uptake in the posterior thorax. On SPECT/CT this uptake was located in a known Elastofibroma Dorsi (ED) previously diagnosed by contrast CT and viewed in a FDG PET/CT. The radioiodine uptake in ED, especially if typical, is not a diagnostic problem in SPECT/CT study, but can be misleading in a study limited to a few planar images, particularly if the uptake occurs asymmetrically, or ED is located in a unsuspected area. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  2. Radiation protection for the eyes of the children experiencing an operation of artificial cochlear implant against CT scan

    International Nuclear Information System (INIS)

    Liu Changsheng; Zheng Xiaohua; Li Maojing; Wei Wenzhou; Pan Ewu; Tang Guangqiao; Zhang Duanlian

    2006-01-01

    Objective: To optimize the CT scanning parameters in pediatric temporal bone examination with artificial cochlear implant and reduce its radiation hazards. Methods: The temporal bones of 87 patients with suspected inner ear disease which include 31 experienced artificial cochlear implant were scanned by HRCT. Regarding adult scan parameters as a criteria, properly adjusted the scanning dose and scanning angle until the quality of CT images was beyond the diagnosis demands. Finally the exposed doses, single scanning CT dose index weighted (CTDI w ) and dose length product (DLP) were analysed. Results: Compared with adult temporal bone scanning, the exposure value and CTDI w were reduced to 66.67%-83.33%, DLP of temporal bone scanning in pediatrics was reduced to 66.67%-83.33%, moreover, the imaging quality of tridimensional reconstruction for inner ear and implant electrode was improved. Conclusion: The proper reduction of CT scan exposure on preoperative and postoperative children with cochlear implants and the proper adjustment of scan angle can significantly reduce the exposure dose to local temporal bone and effectually avoid the damage to lens of children. (authors)

  3. [Automated detection and volumetric segmentation of the spleen in CT scans].

    Science.gov (United States)

    Hammon, M; Dankerl, P; Kramer, M; Seifert, S; Tsymbal, A; Costa, M J; Janka, R; Uder, M; Cavallaro, A

    2012-08-01

    To introduce automated detection and volumetric segmentation of the spleen in spiral CT scans with the THESEUS-MEDICO software. The consistency between automated volumetry (aV), estimated volume determination (eV) and manual volume segmentation (mV) was evaluated. Retrospective evaluation of the CAD system based on methods like "marginal space learning" and "boosting algorithms". 3 consecutive spiral CT scans (thoraco-abdominal; portal-venous contrast agent phase; 1 or 5 mm slice thickness) of 15 consecutive lymphoma patients were included. The eV: 30 cm³ + 0.58 (width × length × thickness of the spleen) and the mV as the reference standard were determined by an experienced radiologist. The aV could be performed in all CT scans within 15.2 (± 2.4) seconds. The average splenic volume measured by aV was 268.21 ± 114.67 cm³ compared to 281.58 ± 130.21 cm³ in mV and 268.93 ± 104.60 cm³ in eV. The correlation coefficient was 0.99 (coefficient of determination (R²) = 0.98) for aV and mV, 0.91 (R² = 0.83) for mV and eV and 0.91 (R² = 0.82) for aV and eV. There was an almost perfect correlation of the changes in splenic volume measured with the new aV and mV (0.92; R² = 0.84), mV and eV (0.95; R² = 0.91) and aV and eV (0.83; R² = 0.69) between two time points. The automated detection and volumetric segmentation software rapidly provides an accurate measurement of the splenic volume in CT scans. Knowledge about splenic volume and its change between two examinations provides valuable clinical information without effort for the radiologist. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Automated detection and volumetric segmentation of the spleen in CT scans

    International Nuclear Information System (INIS)

    Hammon, M.; Dankerl, P.; Janka, R.; Uder, M.; Cavallaro, A.; Kramer, M.; Seifert, S.; Tsymbal, A.; Costa, M.J.

    2012-01-01

    To introduce automated detection and volumetric segmentation of the spleen in spiral CT scans with the THESEUS-MEDICO software. The consistency between automated volumetry (aV), estimated volume determination (eV) and manual volume segmentation (mV) was evaluated. Retrospective evaluation of the CAD system based on methods like ''marginal space learning'' and ''boosting algorithms''. 3 consecutive spiral CT scans (thoraco-abdominal; portal-venous contrast agent phase; 1 or 5 mm slice thickness) of 15 consecutive lymphoma patients were included. The eV: 30 cm 3 + 0.58 (width x length x thickness of the spleen) and the mV as the reference standard were determined by an experienced radiologist. The aV could be performed in all CT scans within 15.2 (± 2.4) seconds. The average splenic volume measured by aV was 268.21 ± 114.67 cm 3 compared to 281.58 ± 130.21 cm 3 in mV and 268.93 ± 104.60 cm 3 in eV. The correlation coefficient was 0.99 (coefficient of determination (R 2 ) = 0.98) for aV and mV, 0.91 (R 2 = 0.83) for mV and eV and 0.91 (R 2 = 0.82) for aV and eV. There was an almost perfect correlation of the changes in splenic volume measured with the new aV and mV (0.92; R 2 = 0.84), mV and eV (0.95; R 2 = 0.91) and aV and eV (0.83; R 2 = 0.69) between two time points. The automated detection and volumetric segmentation software rapidly provides an accurate measurement of the splenic volume in CT scans. Knowledge about splenic volume and its change between two examinations provides valuable clinical information without effort for the radiologist. (orig.)

  5. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, G.R.; Kocier, M.; Calaque, O.; Coulomb, M. [Service Central de Radiologie et Imagerie Medicale, INSERM EMI 9924, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Arbib, F.; Pison, C. [Departement de Medecine Aigue Specialisee (DMAS), CHU Grenoble, CHU, BP 217, 38043, Grenoble Cedex 9 (France); Righini, C. [Service d' Oto Rhino Laryngologie, CHU Grenoble, BP 217, 38043, Grenoble Cedex 9 (France)

    2003-05-01

    The aim of this study was to compare helical CT with fiberoptic bronchoscopy findings to appraise the medium-term results of proximal-airways stenting. Twenty-five patients with 28 endobronchial metallic stents inserted for local advanced malignancy (n=13) or benign diseases (n=12) underwent follow-up CT from 3 days to 50 months (mean 8 months). All studies were obtained using helical CT with subsequent multiplanar reformation and three-dimensional reconstruction including virtual bronchoscopy. The location, shape, and patency of stents and adjacent airway were assessed. The results of CT were compared with the results of fiberoptic bronchoscopy obtained with a mean delay of 2.5 days (SD 9 days) after CT scan. Twelve stents (43%) remained in their original position, patent and without deformity. Sixteen stents were associated with local complications: migration (n=6); external compression with persistent stenosis (n=4); local recurrence of malignancy (n=4); fracture (n=1); and non-congruence between the airway and the stent (n=1). The CT demonstrated all the significant abnormalities demonstrated at fiberoptic bronchoscopy except two moderate stenoses (20%) related to granulomata at the origin of the stent. Ten of 14 stents inserted for benign conditions were without complications as compared with 2 of 14 in malignant conditions (p=0.008). Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. The CT is a useful technique for follow-up of patients who have undergone endobronchial stenting. (orig.)

  6. Follow-up after stent insertion in the tracheobronchial tree: role of helical computed tomography in comparison with fiberoptic bronchoscopy

    International Nuclear Information System (INIS)

    Ferretti, G.R.; Kocier, M.; Calaque, O.; Coulomb, M.; Arbib, F.; Pison, C.; Righini, C.

    2003-01-01

    The aim of this study was to compare helical CT with fiberoptic bronchoscopy findings to appraise the medium-term results of proximal-airways stenting. Twenty-five patients with 28 endobronchial metallic stents inserted for local advanced malignancy (n=13) or benign diseases (n=12) underwent follow-up CT from 3 days to 50 months (mean 8 months). All studies were obtained using helical CT with subsequent multiplanar reformation and three-dimensional reconstruction including virtual bronchoscopy. The location, shape, and patency of stents and adjacent airway were assessed. The results of CT were compared with the results of fiberoptic bronchoscopy obtained with a mean delay of 2.5 days (SD 9 days) after CT scan. Twelve stents (43%) remained in their original position, patent and without deformity. Sixteen stents were associated with local complications: migration (n=6); external compression with persistent stenosis (n=4); local recurrence of malignancy (n=4); fracture (n=1); and non-congruence between the airway and the stent (n=1). The CT demonstrated all the significant abnormalities demonstrated at fiberoptic bronchoscopy except two moderate stenoses (20%) related to granulomata at the origin of the stent. Ten of 14 stents inserted for benign conditions were without complications as compared with 2 of 14 in malignant conditions (p=0.008). Computed tomography is an accurate noninvasive method for evaluating endobronchial stents. The CT is a useful technique for follow-up of patients who have undergone endobronchial stenting. (orig.)

  7. Analysis of lenses absorbed dose in head CT scan with the use of bismuth shielding

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.S.; Santana, P.C., E-mail: fernanda.stephaniebh@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil); Mourão, A.P. [Centro de Educação Tecnológica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Computed Tomography (CT) has become an important tool to diagnose cancer and to obtain additional information for different clinical questions. However, CT scan usually requires a higher radiation exposure than a conventional radiography examination. Head CT scans are used for diagnosis of traumatic head injuries, infections and other diseases with instability. Based on this information, it was studied the dose variation deposited in the lenses and in nearby organs, such as: pharynx, hypophysis and salivary gland with and without the use of bismuth shield. In this study a head CT scan was performed on anthropomorphic male phantom using a GE scanner. Dose measurements have been performed by using radiochromic film strips to register the individual doses in the organs of interest. The results show that the lenses had a reduction of 26% of the dose with the use of the bismuth shield. (author)

  8. Color-coded volume rendering for three-dimensional reconstructions of CT data

    International Nuclear Information System (INIS)

    Rieker, O.; Mildenberger, P.; Thelen, M.

    1999-01-01

    Purpose: To evaluate a technique of colored three-dimensional reconstructions without segmentation. Material and methods: Color-coded volume rendered images were reconstructed from the volume data of 25 thoracic, abdominal, musculoskeletal, and vascular helical CT scans using commercial software. The CT volume rendered voxels were encoded with color in the following manner. Opacity, hue, lightness, and chroma were assigned to each of four classes defined by CT number. Color-coded reconstructions were compared to the corresponding grey-scale coded reconstructions. Results: Color-coded volume rendering enabled realistic visualization of pathologic findings when there was sufficient difference in CT density. Segmentation was necessary in some cases to demonstrate small details in a complex volume. Conclusion: Color-coded volume rendering allowed lifelike visualisation of CT volumes without the need of segmentation in most cases. (orig.) [de

  9. Dose assessment of head CT examination by volume scanning with 320-area-detector

    International Nuclear Information System (INIS)

    Suzuki, Shoichi; Kobayashi, Masanao

    2009-01-01

    CT with the 320-area-detector (320-ADCT), first presented in 2007, still requires further basic studies, particularly in the field of dose assessment, as the CT has been widely spread in clinic due to its many advantages compared with the usual spiral CT. In this paper, the assessment in the title was thereby done in human phantom and a patient with suspicious acute cerebral infarction under different scanning modes (non-spiral, spiral and volume) for their comparison. Machines for 320-ADCT, and non-spiral and spiral CT were Toshiba Aquilion ONE, and Aquilion 64-MD, respectively. Scanning of the phantom and patient was individually conducted under similar conditions of tube voltage/ current, rotation time and length with the same field of view with defined nominal slice thicknesses. Alderson human body phantom in which 240 thermoluminescent dosimeters were indwelled, was used; doses were read by the thermoluminescence dosimeter (TLD) reader model 3000 (Kyokko Co.) after scanning; and effective doses were calculated with reference to ICRP publ. 102/103 equations for patient's head to be 4.2 (64-MDCT) and 6.6 (320-ADCT) mSv, which were respectively 6.4 and 5.4 mSv when estimated using the conversion coefficient and DLP (dose length product) in the texts. It was suggested that the exposure dose at the volume scanning by 320-ADCT can be reduced in the routine examination, and in the exact diagnosis, possibly increases. These doses can be reduced further by optimization of scanning conditions by additional basic investigations. (K.T.)

  10. Hybrid imaging with contrast enhanced CT scan: A nuclear physician's point of view

    International Nuclear Information System (INIS)

    Houzard, C.; Tychyj-Pinel, C.; Defez, D.; Valette, P.J.; Giammarile, F.; Houzard, C.; Valette, P.J.; Giammarile, F.

    2010-01-01

    The ongoing development of hybrid imaging, with physical association of CT scan and PET or SPECT scan, allows integrating morphological and functional information on a single exam. This important technological evolution changes diagnostic and therapeutic strategy in a major manner, essentially in oncology. The possibility to inject intravenously iodinated contrast media in order to enhance CT image contrast is still a controversial question in France. We present our experience in this domain by approaching technical problems and diagnostic advantages. (authors)

  11. Quantitative analysis of titanium-induced artifacts and correlated factors during micro-CT scanning.

    Science.gov (United States)

    Li, Jun Yuan; Pow, Edmond Ho Nang; Zheng, Li Wu; Ma, Li; Kwong, Dora Lai Wan; Cheung, Lim Kwong

    2014-04-01

    To investigate the impact of cover screw, resin embedment, and implant angulation on artifact of microcomputed tomography (micro-CT) scanning for implant. A total of twelve implants were randomly divided into 4 groups: (i) implant only; (ii) implant with cover screw; (iii) implant with resin embedment; and (iv) implants with cover screw and resin embedment. Implants angulation at 0°, 45°, and 90° were scanned by micro-CT. Images were assessed, and the ratio of artifact volume to total volume (AV/TV) was calculated. A multiple regression analysis in stepwise model was used to determine the significance of different factors. One-way ANOVA was performed to identify which combination of factors could minimize the artifact. In the regression analysis, implant angulation was identified as the best predictor for artifact among the factors (P  0.05). Non-embedded implants with the axis parallel to X-ray source of micro-CT produced minimal artifact. Implant angulation and resin embedment affected the artifact volume of micro-CT scanning for implant, while cover screw did not. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Contrast enhanced CT-scans are not comparable to non-enhanced scans in emphysema quantification

    International Nuclear Information System (INIS)

    Heussel, C.P.; Kappes, J.; Hantusch, R.; Hartlieb, S.; Weinheimer, O.; Kauczor, H.-U.; Eberhardt, R.

    2010-01-01

    Systemic, interventional and surgical treatments have gone new ways in treatment of emphysema. For longitudinal therapy monitoring and as end-points for clinical trials, quantification of the disease is necessary. Sensitive, easy to measure, as well as stable and reproducible parameters have to be characterized. One parameter that might affect emphysema quantification is IV contrast enhancement, which might also be indicated. Whether or not the contrast enhanced scan is also suited for emphysema quantification or an additional scan is necessary, a retrospective analysis of 12 adult patients undergoing clinically indicated both, a non-enhanced and enhanced thin section MSCT within a week (median 0 days, range 0-4 days) was done. The in-house YACTA software was used for automatic quantification of lung and emphysema volume, emphysema index, mean lung density, and 5th, 10th, 15th percentile. After IV contrast administration, the median CT derived lung volume decreased mild by 1.1%, while median emphysema volume decreased by relevant 11%. This results in a decrease of median emphysema index by 9%. The median lung density (15th percentile) increased after contrast application by 18 HU (9 HU). CT quantification delivers emphysema values that are clearly affected by IV contrast application. The detected changes after contrast application show the results of higher density in the lung parenchyma. Therefore the amount of quantified emphysema is reduced and the lung density increased after contrast enhancement. In longitudinal analyses, non-enhanced scans should be the reference, while enhanced scans cannot be used.

  13. Multidetector row computed tomography of acute pancreatitis: Utility of single portal phase CT scan in short-term follow up

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Yongwonn [Department of Radiology, Konkuk University Medical Center, 4-12, Hwayang-dong, Gwangjin-gu, Seoul 143-729 (Korea, Republic of); Park, Hee Sun, E-mail: heesun.park@gmail.com [Department of Radiology, Konkuk University Medical Center, 4-12, Hwayang-dong, Gwangjin-gu, Seoul 143-729 (Korea, Republic of); Kim, Young Jun; Jung, Sung Il; Jeon, Hae Jeong [Department of Radiology, Konkuk University Medical Center, 4-12, Hwayang-dong, Gwangjin-gu, Seoul 143-729 (Korea, Republic of)

    2012-08-15

    Objective: The purpose of this study is to evaluate the question of whether nonenhanced CT or contrast enhanced portal phase CT can replace multiphasic pancreas protocol CT in short term monitoring in patients with acute pancreatitis. Materials and methods: This retrospective study was approved by the Institutional Review Board. From April 2006 to May 2010, a total of 52 patients having acute pancreatitis who underwent initial dual phase multidetector row CT (unenhanced, arterial, and portal phase) at admission and a short term (within 30 days) follow up dual phase CT (mean interval 10.3 days, range 3-28 days) were included. Two abdominal radiologists performed an independent review of three sets of follow up CT images (nonenhanced scan, single portal phase scan, and dual phase scan). Interpretation of each image set was done with at least 2-week interval. Radiologists evaluated severity of acute pancreatitis with regard to pancreatic inflammation, pancreatic necrosis, and extrapancreatic complication, based on the modified CT severity index. Scores of each image set were compared using a paired t-test and interobserver agreement was evaluated using intraclass correlation coefficient statistics. Results: Mean scores of sum of CT severity index on nonenhanced scan, portal phase scan, and dual phase scan were 5.7, 6.6, and 6.5 for radiologist 1, and 5.0, 5.6, and 5.8 for radiologist 2, respectively. In both radiologists, contrast enhanced scan (portal phase scan and dual phase scan) showed significantly higher severity score compared with that of unenhanced scan (P < 0.05), while portal phase and dual phase scan showed no significant difference each other. The trend was similar regarding pancreatic inflammation and extrapancreatic complications, in which contrast enhanced scans showed significantly higher score compared with those of unenhanced scan, while no significant difference was observed between portal phase scan and dual phase scan. In pancreatic necrosis

  14. Implementation of dual energy CT scanning

    International Nuclear Information System (INIS)

    Marshall, W.; Hall, E.; Doost-Hoseini, A.; Alvarez, R.; Macovski, A.; Cassel, D.

    1984-01-01

    A prereconstruction method for dual energy (PREDECT) analysis of CT scans is described. In theory, this method can (a) eliminate beam hardening and produce an accuracy comparable with monoenergetic scans and (b) provide the effective atomic number and electron density of any voxel scanned. The implementation proves these statements and eliminates some of the objectionable noise. A phantom was constructed with a cylindrical sleeve-like compartment containing known amounts of high atomic number material simulating a removable skull. Conventional scans, with and without this beam hardener, were done of a water bath containing tubes of high electron and high atomic number material. Dual energy scans were then done for PREDECT. To increase the effective separation of the low and high energy beams by using more appropriate tube filtration, a beam filter changer was fabricated containing erbium, tungsten, aluminum, and steel. Erbium, tungsten, and steel were used at high energy and aluminum, steel, and erbium at low energy for data acquisition. The reconstructions were compared visually and numerically for noise levels with the original steel only filtration. A decrease was found in noise down to approximately one-half the prior level when erbium/aluminum or tungsten/aluminum replaced the steel/steel filter. Erbium and tungsten were equally effective. Steel/erbium and steel/aluminum also significantly reduced image noise. The noise in the photoelectric (P) and Compton (C) images is negatively correlated. At any pixel, if the noise is positive in the P image, it is most probably negative in the C. Using this fact, the noise was reduced by postreconstruction processing

  15. Acute appendicitis: sensitivity, specificity and diagnostic accuracy of thin-section contrast-enhanced CT findings

    International Nuclear Information System (INIS)

    Lee, Ji Yon; Choi, Dong Il; Park, Hae Won; Lee, Young Rae; Kook, Shin Ho; Kwang, Hyon Joo; Kim, Seung Kwon; Chung, Eun Chul

    2002-01-01

    To assess the sensitivity, specificity, and diagnostic accuracy of individual contrast-enhanced helical CT findings of acute appendicitis. We retrospectively reviewed the appendiceal helical CT scans, obtained after intravenous contrast administration (abdomen; 7-mm collimation, abdominopelvic junction; 5-mm collimation), of 50 patients with surgically proven acute appendicitis and 112 with alternative diagnoses. The following parameters were analysed by three radiologists: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), (appendiceal) intraluminal air, abscess, lymphadenopathy, terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The CT findings of acute appendicitis that statistically distinguished it from alternative diagnoses were an enlarged appendix (sensitivity; 92%, specificity; 93%, diagnostic accuracy; 93%), appendiceal wall thickening (for these three parameters: 68%, 96% and 88%, respectively), periappendiceal fat stranding (90%, 79%, 82%), appendiceal wall enhancement (72%, 86%, 82%), appendicolith (16%, 100%, 74%), and focal cecal apical thickening (14%, 100%, 74%) (for each, p<0305). On thin-section contrast-enhanced helical CT, an enlarged appendix and periappendiceal fat stranding were found in 90% or more patients with acute appendicitis. Appendiceal wall thickening and enhancement were alearly demonstrated and significant findings for diagnosis. Less common but specific findings include appendicolith, focal cecal apical thickening and intramural air, can also help us establish a diagnosis of acute appendicitis

  16. Investigation of ultra low-dose scans in the context of quantum-counting clinical CT

    Science.gov (United States)

    Weidinger, T.; Buzug, T. M.; Flohr, T.; Fung, G. S. K.; Kappler, S.; Stierstorfer, K.; Tsui, B. M. W.

    2012-03-01

    In clinical computed tomography (CT), images from patient examinations taken with conventional scanners exhibit noise characteristics governed by electronics noise, when scanning strongly attenuating obese patients or with an ultra-low X-ray dose. Unlike CT systems based on energy integrating detectors, a system with a quantum counting detector does not suffer from this drawback. Instead, the noise from the electronics mainly affects the spectral resolution of these detectors. Therefore, it does not contribute to the image noise in spectrally non-resolved CT images. This promises improved image quality due to image noise reduction in scans obtained from clinical CT examinations with lowest X-ray tube currents or obese patients. To quantify the benefits of quantum counting detectors in clinical CT we have carried out an extensive simulation study of the complete scanning and reconstruction process for both kinds of detectors. The simulation chain encompasses modeling of the X-ray source, beam attenuation in the patient, and calculation of the detector response. Moreover, in each case the subsequent image preprocessing and reconstruction is modeled as well. The simulation-based, theoretical evaluation is validated by experiments with a novel prototype quantum counting system and a Siemens Definition Flash scanner with a conventional energy integrating CT detector. We demonstrate and quantify the improvement from image noise reduction achievable with quantum counting techniques in CT examinations with ultra-low X-ray dose and strong attenuation.

  17. CT portography by multidetector helical CT. Comparison of three rendering models

    International Nuclear Information System (INIS)

    Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki

    2002-01-01

    The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

  18. CT portography by multidetector helical CT. Comparison of three rendering models

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Yoshiharu; Imuta, Masanori; Funama, Yoshinori; Kadota, Masataka; Utsunomiya, Daisuke; Shiraishi, Shinya; Hayashida, Yoshiko; Yamashita, Yasuyuki [Kumamoto Univ. (Japan). School of Medicine

    2002-12-01

    The purpose of this study was to assess the value of multidetector CT portography in visualizing varices and portosystemic collaterals in comparison with conventional portography, and to compare the visualizations obtained by three rendering models (volume rendering, VR; minimum intensity projection, MIP; and shaded surface display, SSD). A total of 46 patients with portal hypertension were examined by CT and conventional portography for evaluation of portosystemic collaterals. CT portography was performed by multidetector CT (MD-CT) scanner with a slice thickness of 2.5 mm and table feed of 7.5 mm. Three types of CT portographic models were generated and compared with transarterial portography. Among 46 patients, 48 collaterals were identified on CT transverse images, while 38 collaterals were detected on transarterial portography. Forty-four of 48 collaterals identified on CT transverse images were visualized with the MIP model, while 34 and 29 collaterals were visualized by the VR and SSD methods, respectively. The average CT value for the portal vein and varices was 198 HU with data acquisition of 50 sec after contrast material injection. CT portography by multidetector CT provides excellent images in the visualization of portosystemic collaterals. The images of collaterals produced by MD-CT are superior to those of transarterial portography. Among the three rendering techniques, MIP provides the best visualization of portosystemic collaterals. (author)

  19. The use of CT-scanning at the medicolegal external postmortem examination and at the forensic autopsy

    DEFF Research Database (Denmark)

    Leth, Peter Mygind

    2006-01-01

    Introduction: Can CT-scanning of deceased at the medico legal external examination improve the selection of cases to autopsy? Is CT-scanning a substitute or a supplement to the traditional forensic autopsy? Material: In 2006 60 deceased individuals from Southern Denmark (counties of Fyn and Sønde...

  20. Effect of clinical information in brain CT scan interpretation : a blinded double crossover study

    International Nuclear Information System (INIS)

    Zhianpour, M.; Janghorbani, M.

    2004-01-01

    Errors and variations in interpretation can happen in clinical imaging. Few studies have examined the biased effect of clinical information on reporting of brain CT scans. In a blinded double crossover design, we studied whether three radiologists were biased by clinical information when making CT scan diagnosis of the brain. Three consultant radiologists in three rounds with at least a one month interval assessed 100 consecutive cases of brain CT scan. In the first round, clinical information was not available and 100 films without clinical information were given to radiologists. In the second round, the same 100 films were given and true clinical information was available. In the third round, the same 100 films were given and false clinical information was allocated. In 180 cases (60%) the evaluation resulted in the same diagnosis on all three occasions (95% confidence interval (CI): 54.5, 65.5), whereas 120(40%; 95% CI:34.5, 45.5) sets were evaluated differently. 48 cases (16%; 95% CI:11.9,20.1) had discordant evaluation with true and 33 (11%; 95% CI:7.5, 14.5) with false clinical information. Discordance without and with true and false clinical information was 39 (13%; 95% CI:9.2, 16.8). Correct clinical information improves the brain CT report, while the report became less accurate false clinical information was allocated. These results indicate that radiologists are biased by clinical information when reporting brian CT scans

  1. How to distinguish between bleeding and coagulated extradural hematomas on the plain CT scanning

    International Nuclear Information System (INIS)

    Petersen, O.F.; Espersen, J.O.

    1984-01-01

    Four types of extradural hematoma could be separated at examination of the plain CT scan in 54 extradural hematomas. Two major groups appear: the still bleeding hematoma showing either generally low attenuation values of ''holes'', and a coagulated homogenous type with generally high attenuation values. The attenuation values of the bleeding-liquid part of hematoma - were correlated to hemoglobin concentration in blood, to which clots were not related. Seven extradural hematomas grew and coagulated on repeated preoperative CT scans. In two cases intravenous contrast was given to the bleeding type of hematoma, and the contrast media appeared in ''holes'', but not in areas of high attenuation value. It is easy to distinguish between the different types of hematoma on the plain CT scan, and the separation by eye between the still bleeding and the coagulated extradural hematoma seems reliable. (orig.)

  2. Myocardial perfusion imaging and coronary calcium scoring with a two-slice SPECT/CT system: can the attenuation map be calculated from the calcium scoring CT scan?

    Energy Technology Data Exchange (ETDEWEB)

    Wenning, Christian; Rahbar, Kambiz; Schober, Otmar; Stegger, Lars [University of Muenster, Department of Nuclear Medicine, Muenster (Germany); Vrachimis, Alexis; Schaefers, Michael [University of Muenster, Department of Nuclear Medicine, Muenster (Germany); University of Muenster, European Institute for Molecular Imaging, Muenster (Germany)

    2013-07-15

    Coronary artery calcium scoring can complement myocardial perfusion imaging (MPI). The purpose of this study was to evaluate the feasibility and accuracy of using the CalciumScore-CT derived from a combined SPECT/CT device also for SPECT attenuation correction (AC). The study group comprised 99 patients who underwent both post-stress and rest MPI using a two-slice SPECT/CT system. For AC, one of the two scans was accompanied by a CalciumScore-CT scan (CalciumScore-CTAC) and the other by a conventional spiral CT (AttenCorr-CT) scan (AttenCorr-CTAC). In 48 patients the CalciumScore-CT scan was acquired with the post-stress scan and the AttenCorr-CT scan with the rest scan, and in 51 patients the order was reversed. The accuracy of the images based on AC was determined qualitatively by consensus reading with respect to the clinical diagnoses as well as quantitatively by comparing the perfusion summed stress scores (SSS) and the summed rest scores (SRS) between attenuation-corrected and uncorrected images. In comparison to the uncorrected images CalciumScore-CTAC led to regional inaccuracies in 14 of 51 of studies (27.5 %) versus 12 of 48 studies (25 %) with AttenCorr-CTAC for the stress studies and in 5 of 48 (10 %) versus 1 of 51 (2 %) for the rest studies, respectively. This led to intermediate and definite changes in the final diagnosis (ischaemia and/or scarring) in 12 % of the studies (12 of 99) and in 7 % of the studies (7 of 99) with CalciumScore-CTAC and in 9 % of the studies (9 of 99) and 4 % of the studies (4 of 99) with AttenCorr-CTAC. Differences in SSS and SRS with respect to the uncorrected images were greater for the CalciumScore-CTAC images than for the AttenCorr-CTAC images ({Delta}SSS 4.5 {+-} 5.6 and 2.1 {+-} 4.4, p = 0.023; {Delta}SRS 4.2 {+-} 4.9 and 1.6 {+-} 3.2, p = 0.004, respectively). Using the same CT scan for calcium scoring and SPECT AC is feasible. Image interpretation must, however, include uncorrected images since CT-based AC relatively

  3. Volumetric gain of the human pancreas after left partial pancreatic resection: A CT-scan based retrospective study.

    Science.gov (United States)

    Phillip, Veit; Zahel, Tina; Danninger, Assiye; Erkan, Mert; Dobritz, Martin; Steiner, Jörg M; Kleeff, Jörg; Schmid, Roland M; Algül, Hana

    2015-01-01

    Regeneration of the pancreas has been well characterized in animal models. However, there are conflicting data on the regenerative capacity of the human pancreas. The aim of the present study was to assess the regenerative capacity of the human pancreas. In a retrospective study, data from patients undergoing left partial pancreatic resection at a single center were eligible for inclusion (n = 185). Volumetry was performed based on 5 mm CT-scans acquired through a 256-slice CT-scanner using a semi-automated software. Data from 24 patients (15 males/9 females) were included. Mean ± SD age was 68 ± 11 years (range, 40-85 years). Median time between surgery and the 1st postoperative CT was 9 days (range, 0-27 days; IQR, 7-13), 55 days (range, 21-141 days; IQR, 34-105) until the 2nd CT, and 191 days (range, 62-1902; IQR, 156-347) until the 3rd CT. The pancreatic volumes differed significantly between the first and the second postoperative CT scans (median volume 25.6 mL and 30.6 mL, respectively; p = 0.008) and had significantly increased further by the 3rd CT scan (median volume 37.9 mL; p = 0.001 for comparison with 1st CT scan and p = 0.003 for comparison with 2nd CT scan). The human pancreas shows a measurable and considerable potential of volumetric gain after partial resection. Multidetector-CT based semi-automated volume analysis is a feasible method for follow-up of the volume of the remaining pancreatic parenchyma after partial pancreatectomy. Effects on exocrine and endocrine pancreatic function have to be evaluated in a prospective manner. Copyright © 2015 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  4. Does head CT scan pathology predict outcome after mild traumatic brain injury?

    Science.gov (United States)

    Lannsjö, M; Backheden, M; Johansson, U; Af Geijerstam, J L; Borg, J

    2013-01-01

    More evidence is needed to forward our understanding of the key determinants of poor outcome after mild traumatic brain injury (MTBI). A large, prospective, national cohort of patients was studied to analyse the effect of head CT scan pathology on the outcome. One-thousand two-hundred and sixty-two patients with MTBI (Glasgow Coma Scale score 15) at 39 emergency departments completed a study protocol including acute head CT scan examination and follow-up by the Rivermead Post Concussion Symptoms Questionnaire and the Glasgow Outcome Scale Extended (GOSE) at 3 months after MTBI. Binary logistic regression was used for the assessment of prediction ability. In 751 men (60%) and 511 women (40%), with a mean age of 30 years (median 21, range 6-94), we observed relevant or suspect relevant pathologic findings on acute CT scan in 52 patients (4%). Patients aged below 30 years reported better outcome both with respect to symptoms and GOSE as compared to patients in older age groups. Men reported better outcome than women as regards symptoms (OR 0.64, CI 0.49-0.85 for ≥3 symptoms) and global function (OR 0.60, CI 0.39-0.92 for GOSE 1-6). Pathology on acute CT scan examination had no effect on self-reported symptoms or global function at 3 months after MTBI. Female gender and older age predicted a less favourable outcome. The findings support the view that other factors than brain injury deserve attention to minimize long-term complaints after MTBI. © 2012 The Author(s) European Journal of Neurology © 2012 EFNS.

  5. A morphological study of the mandibular molar region using reconstructed helical computed tomographic images

    International Nuclear Information System (INIS)

    Tsuno, Hiroaki; Noguchi, Makoto; Noguchi, Akira; Yoshida, Keiko; Tachinami, Yasuharu

    2010-01-01

    This study investigated the morphological variance in the mandibular molar region using reconstructed helical computed tomographic (CT) images. In addition, we discuss the necessity of CT scanning as part of the preoperative assessment process for dental implantation, by comparing the results with the findings of panoramic radiography. Sixty patients examined using CT as part of the preoperative assessment for dental implantation were analyzed. Reconstructed CT images were used to evaluate the bone quality and cross-sectional bone morphology of the mandibular molar region. The mandibular cortical index (MCI) and X-ray density ratio of this region were assessed using panoramic radiography in order to analyze the correlation between the findings of the CT images and panoramic radiography. CT images showed that there was a decrease in bone quality in cases with high MCI. Cross-sectional CT images revealed that the undercuts on the lingual side in the highly radiolucent areas in the basal portion were more frequent than those in the alveolar portion. This study showed that three-dimensional reconstructed CT images can help to detect variances in mandibular morphology that might be missed by panoramic radiography. In conclusion, it is suggested that CT should be included as an important examination tool before dental implantation. (author)

  6. Reduction in radiation dose with reconstruction technique in the brain perfusion CT

    Science.gov (United States)

    Kim, H. J.; Lee, H. K.; Song, H.; Ju, M. S.; Dong, K. R.; Chung, W. K.; Cho, M. S.; Cho, J. H.

    2011-12-01

    The principal objective of this study was to verify the utility of the reconstruction imaging technique in the brain perfusion computed tomography (PCT) scan by assessing reductions in the radiation dose and analyzing the generated images. The setting used for image acquisition had a detector coverage of 40 mm, a helical thickness of 0.625 mm, a helical shuttle mode scan type and a rotation time of 0.5 s as the image parameters used for the brain PCT scan. Additionally, a phantom experiment and an animal experiment were carried out. In the phantom and animal experiments, noise was measured in the scanning with the tube voltage fixed at 80 kVp (kilovolt peak) and the level of the adaptive statistical iterative reconstruction (ASIR) was changed from 0% to 100% at 10% intervals. The standard deviation of the CT coefficient was measured three times to calculate the mean value. In the phantom and animal experiments, the absorbed dose was measured 10 times under the same conditions as the ones for noise measurement before the mean value was calculated. In the animal experiment, pencil-type and CT-dedicated ionization chambers were inserted into the central portion of pig heads for measurement. In the phantom study, as the level of the ASIR changed from 0% to 100% under identical scanning conditions, the noise value and dose were proportionally reduced. In our animal experiment, the noise value was lowest when the ASIR level was 50%, unlike in the phantom study. The dose was reduced as in the phantom study.

  7. Automated volumetry of temporal horn of lateral ventricle for detection of Alzheimer's disease in CT scan

    Science.gov (United States)

    Takahashi, Noriyuki; Kinoshita, Toshibumi; Ohmura, Tomomi; Matsuyama, Eri; Toyoshima, Hideto

    2018-02-01

    The rapid increase in the incidence of Alzheimer's disease (AD) has become a critical issue in low and middle income countries. In general, MR imaging has become sufficiently suitable in clinical situations, while CT scan might be uncommonly used in the diagnosis of AD due to its low contrast between brain tissues. However, in those countries, CT scan, which is less costly and readily available, will be desired to become useful for the diagnosis of AD. For CT scan, the enlargement of the temporal horn of the lateral ventricle (THLV) is one of few findings for the diagnosis of AD. In this paper, we present an automated volumetry of THLV with segmentation based on Bayes' rule on CT images. In our method, first, all CT data sets are normalized into an atlas by using linear affine transformation and non-linear wrapping techniques. Next, a probability map of THLV is constructed in the normalized data. Then, THLV regions are extracted based on Bayes' rule. Finally, the volume of the THLV is evaluated. This scheme was applied to CT scans from 20 AD patients and 20 controls to evaluate the performance of the method for detecting AD. The estimated THLV volume was markedly increased in the AD group compared with the controls (P < .0001), and the area under the receiver operating characteristic curve (AUC) was 0.921. Therefore, this computerized method may have the potential to accurately detect AD on CT images.

  8. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters).

    Science.gov (United States)

    Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

    2016-01-07

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  9. Comparative study of CT scan findings and intellectual function between Parkinson's disease and vascular Parkinsonism

    International Nuclear Information System (INIS)

    Indo, Toshikatsu

    1986-01-01

    Comparative study of CT scan findings and intellectual function between 64 cases with Parkinson's disease and 25 cases with vascular Parkinsonism was carried out. The rate of abnormality of CT scan findings, either ventricular dilatation or widening of sulci, in vascular Parkinsonism was strikingly high compared with Parkinson's disease. Patients could be divided into three groups according to the degree of overall abnormalities of CT scan findings (group A: markedly abnormal, group B: mildly abnormal, group C: normal). Incidences of group A were 9.4 % in Parkinson's disease and 52 % in vascular Parkinsonism, whereas those of group C were 56 % in the former and 28 % in the latter. All patients of group A were over 65 years of age in Parkinson's disease, but one-third of patients in group A were under 59 years of age in vascular Parkinsonism. Moreover, in vascular Parkinsonism, the level of disability was directly proportional to the abnormality of CT scan findings. The rate of predementia and dementia classified by Hasegawa's intelligence scale was 12.5 % in Parkinson's disease and 48 % in vascular Parkinsonism. No difference was found between the mean values of intelligence scale and background factors in Parkinson's disease. On the other hand, the mean value was significantly low in proportion to the poverty of L-dopa effect in vascular Parkinsonism. From these results, the abnormality of CT scan findings and intellectual impairment were probably related to the cerebral pathological process in vascular Parkinsonism, but these relationship was absent in Parkinson's disease. (author)

  10. Comparative study of CT scan findings and intellectual function between Parkinson's disease and vascular Parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Indo, Toshikatsu

    1986-01-01

    Comparative study of CT scan findings and intellectual function between 64 cases with Parkinson's disease and 25 cases with vascular Parkinsonism was carried out. The rate of abnormality of CT scan findings, either ventricular dilatation or widening of sulci, in vascular Parkinsonism was strikingly high compared with Parkinson's disease. Patients could be divided into three groups according to the degree of overall abnormalities of CT scan findings (group A: markedly abnormal, group B: mildly abnormal, group C: normal). Incidences of group A were 9.4 % in Parkinson's disease and 52 % in vascular Parkinsonism, whereas those of group C were 56 % in the former and 28 % in the latter. All patients of group A were over 65 years of age in Parkinson's disease, but one-third of patients in group A were under 59 years of age in vascular Parkinsonism. Moreover, in vascular Parkinsonism, the level of disability was directly proportional to the abnormality of CT scan findings. The rate of predementia and dementia classified by Hasegawa's intelligence scale was 12.5 % in Parkinson's disease and 48 % in vascular Parkinsonism. No difference was found between the mean values of intelligence scale and background factors in Parkinson's disease. On the other hand, the mean value was significantly low in proportion to the poverty of L-dopa effect in vascular Parkinsonism. From these results, the abnormality of CT scan findings and intellectual impairment were probably related to the cerebral pathological process in vascular Parkinsonism, but these relationship was absent in Parkinson's disease.

  11. Recent micro-CT scanner developments at UGCT

    Energy Technology Data Exchange (ETDEWEB)

    Dierick, Manuel, E-mail: Manuel.Dierick@UGent.be [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Van Loo, Denis, E-mail: info@XRE.be [XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Masschaele, Bert [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); XRE, X-Ray Engineering bvba, De Pintelaan 111, 9000 Ghent (Belgium); Van den Bulcke, Jan [UGCT-Woodlab-UGent, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent (Belgium); Van Acker, Joris, E-mail: Joris.VanAcker@UGent.be [UGCT-Woodlab-UGent, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent (Belgium); Cnudde, Veerle, E-mail: Veerle.Cnudde@UGent.be [UGCT-SGIG, Department of Geology and Soil Science, Faculty of Sciences, Ghent University, Krijgslaan 281, S8, 9000 Ghent (Belgium); Van Hoorebeke, Luc, E-mail: Luc.VanHoorebeke@UGent.be [UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium)

    2014-04-01

    This paper describes two X-ray micro-CT scanners which were recently developed to extend the experimental possibilities of microtomography research at the Centre for X-ray Tomography ( (www.ugct.ugent.be)) of the Ghent University (Belgium). The first scanner, called Nanowood, is a wide-range CT scanner with two X-ray sources (160 kV{sub max}) and two detectors, resolving features down to 0.4 μm in small samples, but allowing samples up to 35 cm to be scanned. This is a sample size range of 3 orders of magnitude, making this scanner well suited for imaging multi-scale materials such as wood, stone, etc. Besides the traditional cone-beam acquisition, Nanowood supports helical acquisition, and it can generate images with significant phase-contrast contributions. The second scanner, known as the Environmental micro-CT scanner (EMCT), is a gantry based micro-CT scanner with variable magnification for scanning objects which are not easy to rotate in a standard micro-CT scanner, for example because they are physically connected to external experimental hardware such as sensor wiring, tubing or others. This scanner resolves 5 μm features, covers a field-of-view of about 12 cm wide with an 80 cm vertical travel range. Both scanners will be extensively described and characterized, and their potential will be demonstrated with some key application results.

  12. Recent micro-CT scanner developments at UGCT

    International Nuclear Information System (INIS)

    Dierick, Manuel; Van Loo, Denis; Masschaele, Bert; Van den Bulcke, Jan; Van Acker, Joris; Cnudde, Veerle; Van Hoorebeke, Luc

    2014-01-01

    This paper describes two X-ray micro-CT scanners which were recently developed to extend the experimental possibilities of microtomography research at the Centre for X-ray Tomography ( (www.ugct.ugent.be)) of the Ghent University (Belgium). The first scanner, called Nanowood, is a wide-range CT scanner with two X-ray sources (160 kV max ) and two detectors, resolving features down to 0.4 μm in small samples, but allowing samples up to 35 cm to be scanned. This is a sample size range of 3 orders of magnitude, making this scanner well suited for imaging multi-scale materials such as wood, stone, etc. Besides the traditional cone-beam acquisition, Nanowood supports helical acquisition, and it can generate images with significant phase-contrast contributions. The second scanner, known as the Environmental micro-CT scanner (EMCT), is a gantry based micro-CT scanner with variable magnification for scanning objects which are not easy to rotate in a standard micro-CT scanner, for example because they are physically connected to external experimental hardware such as sensor wiring, tubing or others. This scanner resolves 5 μm features, covers a field-of-view of about 12 cm wide with an 80 cm vertical travel range. Both scanners will be extensively described and characterized, and their potential will be demonstrated with some key application results

  13. Study of effect of different CT scanning protocols on HU variation and their impact on TPS calculations

    International Nuclear Information System (INIS)

    Mahur, Mamta; Sharma, Richa; Sasindaran, M.; Singh, Anshu; Gedam, Varsha; Negi, P.S.; Grover, R.K.

    2016-01-01

    Computer tomographic (CT) scans are used to correct for tissue inhomogeneties in radiotherapy treatment planning. In order to guarantee a precise treatment, it is important to obtain the relationship between CT Hounsfield units and relative electron densities, which is the basic input for radiotherapy planning systems which consider tissue heterogeneities. The purpose of this study is to investigate the influence of different CT scan parameters (kVp, mAs) on uniformity of CT numbers versus relative electron density (HURED) curves and their different dosimetric impact

  14. Multiphasic helical Computed Tomography of hepatocellular carcinoma. Evaluation after various percutaneous ablation procedures

    International Nuclear Information System (INIS)

    Catalano, O.; Esposito, M.; Lobianco, R.; Cusati, B.; Altei, F.; Siani, A.

    1999-01-01

    The purpose of this paper is to report the personal experience with helical CT evaluation of hepatocellular carcinoma treated with various percutaneous interventional procedures. From December 1996 to September 1998 it were examined with helical CT 41 patients (73 nodules in all) with hepatocellular carcinoma treated with percutaneous ablation therapies: conventional ethanol injection in 18 subjects (31 nodules), one-shot ethanol injection 3 (8 nodules), radiofrequency thermal ablation in 16 (25 nodules), and combined chemo embolization and ethanol injection in 4 (9 nodules). CT performed was 4-27 days after the last session, acquiring biphasic volumetric images in 14 patients and triphasic volumetric images in 27. A second treatment with subsequent CT study was performed for 28 lesions; 15 underwent 3 serial studies and 6 underwent 4 studies. Compared with pretreatment findings, the diameter was unchanged in 62% of the nodules and increased in 38%. Morphology was unchanged in 63% of the lesions while in 37% a mild deformation toward the needle path or a more regular and round shape was evident. Borders were unchanged in 37% of the cases and modified in 63%, appearing well-defined in 73% and ill-defined in 27%. The necrotic portion had a low attenuation with a nodule-to-parenchyma gradient more evident on delayed than on venous and finally arterial acquisitions; 8% of the lesions were not recognizable on unenhanced scans. During the arterial phase the residual tumor appeared hyperdense in 97% of the nodules and isodense in 3%, while during the portal phase it was hyperdense in 22%, isodense in 28% and hypodense in 50%, and during the delayed phase hypodense in 100%. Residual viable tissue was identified in 44% of the nodules and quantified as 100% in 1% of all lesions, > 75% in 3%, > 50% in 4%, > 25% in 23%. In conclusion, multiple-phase helical CT allows optimal depiction of primitive liver nodules treated with percutaneous interventional procedures and has a

  15. Differences in MRI findings in cases showing ring-enhancement on a CT scan

    International Nuclear Information System (INIS)

    Tokiwa, Kaichi; Hashimoto, Takashi; Miyasaka, Yoshio; Yada, Kenzoh; Kan, Shinichi; Takagi, Hiroshi.

    1990-01-01

    It is sometimes difficult to differentiate between a brain abscess and a tumor, for both show ring-enhancement on a CT scan. The present authors have studied the benefit of MRI for the differential diagnosis of these two lesions. The subjects of this study were 6 cases of brain abscess and 10 cases of brain tumor, all of them showing ring-enhancement on a CT scan. The MRI findings were compared with those of the CT scan taken at almost the same time, especially focussing on the difference in the ring-enhancement. In 5 out of the 6 cases of brain abscess, T 2 -weighted MRI demonstrated a comparatively thin and homogeneous low-intensity, round rim. In the cases of brain tumor, however, none of the cases demonstrated this typical low-intensity, round rim; rather, in them the rim was thick and irregular. The authors can conclude that those MRI findings can serve as important differential diagnostic findings between brain abscess and tumor; also, MRI may be used as a landmark for terminating the administration of antibiotics in cases of brain abscess. (author)

  16. Clinical study of acute cerebral infarction with a midline shift on the CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Takemae, T; Mizukami, M; Kin, H; Kawase, T; Araki, G [Mihara Memorial Hospital, Isezaki, Gunma (Japan)

    1978-12-01

    Twenty-one cases of acute cerebral infarction with a midline shift on the CT scan were studied with respect to the development of the midline shift, the angiographic findings, the clinical pictures and the outcome of these patients. The CT findings of hemorrhagic infarction were also studied. No cases showed a midline shift on a CT scan taken within 6 hours after the onset. A midline shift was, however, noted as early as 9 hours after the onset, and it reached its peak between the 2nd and 7th day of the onset. It gradually disappeared by the end of the third week. Hemorrhagic infarction was diagnosed in 6 patients by either spinal tap or autopsy. The CT findings of these hemorrhagic infarction were divided into two types, solid hemorrhages with an unequivocal high density within the low-density area, and small, scattered hemorrhagic of almost the same density as normal brain tissue within the low-density area. In 19 of 21 patients, an round-edged occlusion and/or embolus were observed on the initial angiograms. The recanalization of the occluded vessels was proved in 10 of 14 patients by subsequent angiographic studies. Twenty of 21 patients showed a sudden development of neurological symptoms, and 15 patients had a history of various kinds of heart disease, such as atrial fibrillation, valvular heart disease and myocardial infarction. The patients had atrial fibrillation on EKG on admission. These angiographic findings and clinical pictures strongly suggest that the infarction with a midline shift on the CT scan may be caused by a cerebral embolism of cardiac origin. Eight patients died of cerebral herniation between the 2nd and 6th day of the onset. Taking these poor outcomes into consideration, surgical as well as medical decompression of the brain would seem to be most important when the CT scan shows a midline shift.

  17. Dose profile variation with voltage in head CT scans using radiochromic films

    Science.gov (United States)

    Mourão, A. P.; Alonso, T. C.; DaSilva, T. A.

    2014-02-01

    The voltage source used in an X-ray tube is an important part of defining the generated beam spectrum energy profile. The X-ray spectrum energy defines the X-ray beam absorption as well as the characteristics of the energy deposition in an irradiated object. Although CT scanners allow one to choose between four different voltage values, most of them employ a voltage of 120 kV in their scanning protocols, regardless of the patient characteristics. Based on this fact, this work investigated the deposited dose in a polymethyl methacrylate (PMMA) cylindrical head phantom. The entire volume was irradiated twice. Two CT scanning protocols were used with two different voltage values: 100 and 120 kV. The phantom volume was irradiated, and radiochromic films were employed to record dose profiles. Measurements were conducted with a calibrated pencil ionization chamber, which was positioned in the center and in four peripheral bores of the head PMMA phantom, to calibrate the radiochromic films. The central slice was then irradiated. This procedure allowed us to find the conversion factors necessary to obtain dose values recorded in the films. The data obtained allowed us to observe the dose variation profile inside the phantom head as well as in the peripheral and central regions. The peripheral region showed higher dose values than those of the central region for scans using both voltage values: approximately 31% higher for scanning with 120 kV and 25% higher with 100 kV. Doses recorded with the highest voltage are significantly higher, approximately 50% higher in the peripheral region and 40% higher in the central region. A longitudinal variation could be observed, and the maximum dose was recorded at the peripheral region, at the midpoint of the longitudinal axis. The obtained results will most likely contribute to the dissemination of proper procedure as well as to optimize dosimetry and tests of quality control in CT because the choice of protocols with different voltage

  18. A coarse-to-fine approach for pericardial effusion localization and segmentation in chest CT scans

    Science.gov (United States)

    Liu, Jiamin; Chellamuthu, Karthik; Lu, Le; Bagheri, Mohammadhadi; Summers, Ronald M.

    2018-02-01

    Pericardial effusion on CT scans demonstrates very high shape and volume variability and very low contrast to adjacent structures. This inhibits traditional automated segmentation methods from achieving high accuracies. Deep neural networks have been widely used for image segmentation in CT scans. In this work, we present a two-stage method for pericardial effusion localization and segmentation. For the first step, we localize the pericardial area from the entire CT volume, providing a reliable bounding box for the more refined segmentation step. A coarse-scaled holistically-nested convolutional networks (HNN) model is trained on entire CT volume. The resulting HNN per-pixel probability maps are then threshold to produce a bounding box covering the pericardial area. For the second step, a fine-scaled HNN model is trained only on the bounding box region for effusion segmentation to reduce the background distraction. Quantitative evaluation is performed on a dataset of 25 CT scans of patient (1206 images) with pericardial effusion. The segmentation accuracy of our two-stage method, measured by Dice Similarity Coefficient (DSC), is 75.59+/-12.04%, which is significantly better than the segmentation accuracy (62.74+/-15.20%) of only using the coarse-scaled HNN model.

  19. CT of multiple sclerosis: reassessment of delayed scanning with high doses of contrast material

    International Nuclear Information System (INIS)

    Spiegel, S.M.; Vinuela, F.; Fox, A.J.; Pelz, D.M.

    1985-01-01

    A prospective study involving 87 patients was carried out to evaluate the necessity for a high dose of contrast material in addition to delayed computed tomographic (CT) scanning for optimal detection of the lesions of multiple sclerosis in the brain. In patients with either clinically definite multiple sclerosis or laboratory-supported definite multiple sclerosis, CT scans were obtained with a uniform protocol. Lesions consistent with multiple sclerosis were demonstrated on the second scan in 54 patients. In 36 of these 54 patients, the high-dose delayed scan added information. These results are quite similar to those of a previous study from this institution using different patients, in whom the second scan was obtained immediately after the bolus injection of contrast material containing 40 g of organically bound iodine. The lack of real difference in the results of the two studies indicate that the increased dose, not just the delay in scanning, is necessary for a proper study

  20. Feasibility of using intravenous contrast-enhanced computed tomography (CT) scans in lung cancer treatment planning

    International Nuclear Information System (INIS)

    Xiao Jianghong; Zhang Hong; Gong Youling; Fu Yuchuan; Tang Bin; Wang Shichao; Jiang Qingfeng; Li Ping

    2010-01-01

    Background and purpose: To investigate the feasibility of using intravenous contrast-enhanced computed tomography (CT) scans in 3-dimensional conformal radiotherapy (3D-CRT), stereotactic body radiation therapy (SBRT) and intensity-modulated radiotherapy (IMRT) treatment planning for lung cancers, respectively. Materials and methods: Twelve patients with bulky lung tumors and 14 patients with small lung tumors were retrospectively analyzed. Each patient took two sets of CT in the same position with active breathing control (ABC) technique before and after intravenous contrast agent (CA) injections. Bulky tumors were planned with 3D-CRT, while SBRT plans were generated for patients with small tumors based on CT scans with intravenous CA. In addition, IMRT plans were generated for patients with bulky tumors to continue on a planning study. All plans were copied and replaced on the scans without intravenous CA. The radiation doses calculated from the two sets of CTs were compared with regard to planning volumes (PTV), the organ at-risk (OAR) and the lungs using Wilcoxon's signed rank test. Results: In comparisons for 3D-CRT plans, CT scans with intravenous CA reduced the mean dose and the maximum dose of PTV with significant differences (p 95 ) for targets, respectively (p < 0.05). There was no statistical significance for lung parameters between two sets of scans in SBRT plans and IMRT plans. Conclusions: The enhanced CT scans can be used for both target delineation and treatment planning in 3D-CRT. The dose difference caused by intravenous CA is small. But for SBRT and IMRT, the minimum irradiation dose in targets may be estimated to be increased up to 2.71% while the maximum dose may be estimated to be decreased up to 1.36%. However, the difference in dose distribution in most cases were found to be clinical tolerable.

  1. Assessment value of quantitative indexes of pancreatic CT perfusion scanning for malignant degree of pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Jiang-Xia Lei

    2016-10-01

    Full Text Available Objective: To analyze the assessment value of the quantitative indexes of pancreatic CT perfusion scanning for malignant degree of pancreatic cancer. Methods: A total of 58 patients with space-occupying pancreatic lesions were divided into 20 patients with pancreatic cancer and 38 patients with benign pancreatic lesions after pancreatic CT perfusion. Patients with pancreatic cancer received palliative surgery, and the cancer tissue and para-carcinoma tissue specimens were collected during operation. The differences in pancreatic CT perfusion scanning parameter values and serum tumor marker levels were compared between patients with pancreatic cancer and patients with benign pancreatic lesions, mRNA expression levels of malignant molecules in pancreatic cancer tissue and para-carcinoma tissue were further determined, and the correlation between pancreatic CT perfusion scanning parameter values and malignant degree of pancreatic cancer was analyzed. Results: CT perfusion scanning BF, BV and Per values of patients with pancreatic cancer were lower than those of patients with benign pancreatic lesions; serum CA19-9, CEA, CA125 and CA242 levels were higher than those of patients with benign pancreatic lesions (P<0.05; mRNA expression levels of Bcl-2, Bcl-xL and survivin in pancreatic cancer tissue samples were higher than those in paracarcinoma tissue samples, and mRNA expression levels of P53 and Bax were lower than those in para-carcinoma tissue samples (P<0.05; CT perfusion scanning parameters BF, BV and Per values of patients with pancreatic cancer were negatively correlated with CA19-9, CEA, CA125 and CA242 levels in serum as well as mRNA expression levels of Bcl-2, Bcl-xL and survivin in pancreatic cancer tissue, and positively correlated with mRNA expression levels of P53 and Bax in pancreatic cancer tissue (P<0.05. Conclusions: Pancreatic CT perfusion scanning is a reliable way to judge the malignant degree of pancreatic cancer and plays a

  2. Community-Acquired Pneumonia Visualized on CT Scans but Not Chest Radiographs: Pathogens, Severity, and Clinical Outcomes.

    Science.gov (United States)

    Upchurch, Cameron P; Grijalva, Carlos G; Wunderink, Richard G; Williams, Derek J; Waterer, Grant W; Anderson, Evan J; Zhu, Yuwei; Hart, Eric M; Carroll, Frank; Bramley, Anna M; Jain, Seema; Edwards, Kathryn M; Self, Wesley H

    2018-03-01

    The clinical significance of pneumonia visualized on CT scan in the setting of a normal chest radiograph is uncertain. In a multicenter prospective surveillance study of adults hospitalized with community-acquired pneumonia (CAP), we compared the presenting clinical features, pathogens present, and outcomes of patients with pneumonia visualized on a CT scan but not on a concurrent chest radiograph (CT-only pneumonia) and those with pneumonia visualized on a chest radiograph. All patients underwent chest radiography; the decision to obtain CT imaging was determined by the treating clinicians. Chest radiographs and CT images were interpreted by study-dedicated thoracic radiologists blinded to the clinical data. The study population included 2,251 adults with CAP; 2,185 patients (97%) had pneumonia visualized on chest radiography, whereas 66 patients (3%) had pneumonia visualized on CT scan but not on concurrent chest radiography. Overall, these patients with CT-only pneumonia had a clinical profile similar to those with pneumonia visualized on chest radiography, including comorbidities, vital signs, hospital length of stay, prevalence of viral (30% vs 26%) and bacterial (12% vs 14%) pathogens, ICU admission (23% vs 21%), use of mechanical ventilation (6% vs 5%), septic shock (5% vs 4%), and inhospital mortality (0 vs 2%). Adults hospitalized with CAP who had radiological evidence of pneumonia on CT scan but not on concurrent chest radiograph had pathogens, disease severity, and outcomes similar to patients who had signs of pneumonia on chest radiography. These findings support using the same management principles for patients with CT-only pneumonia and those with pneumonia seen on chest radiography. Copyright © 2017 American College of Chest Physicians. All rights reserved.

  3. Dose reduction for CT in children with cystic fibrosis: is it feasible to reduce the number of images per scan?

    International Nuclear Information System (INIS)

    Jong, Pim A. de; Tiddens, Harm A.W.M.; Nakano, Yasutaka; Lequin, Maarten H.

    2006-01-01

    Reducing the dose for each CT scan is important for children with cystic fibrosis (CF). To determine whether the number of CT images and therefore the dose per CT scan could be reduced without any significant loss of information in children with CF. A cohort of children with CF was followed with biennial surveillance CT scans, obtained in inspiration after a voluntary breath-hold as 1-mm thick images at 10-mm intervals from lung apex to base. A random set of 20 baseline CT scans and 10 follow-up CT scans were blinded. Sets of every image (10-mm intervals), every second image (20-mm intervals), every third image (30-mm intervals) and a selection of three and five images were scored randomly using a published CT scoring system by one experienced observer. The 20 subjects were 10 years of age with a range of 3.7-17.6 years at baseline. Fewer CT images resulted in a significantly lower (less abnormal) CT score and the number of patients positive for abnormalities decreased subsequently. At intervals greater than 20 mm no significant change in CT score over 2 years could be detected, while the CT scores at 10-mm (P=0.02) and 20-mm (P=0.02) intervals worsened significantly. A reduction in the number of inspiratory CT images by increasing the interval between images to greater than 10 mm is not a valid option for radiation dose reduction in children with CF. (orig.)

  4. Automated Agatston score computation in non-ECG gated CT scans using deep learning

    Science.gov (United States)

    Cano-Espinosa, Carlos; González, Germán.; Washko, George R.; Cazorla, Miguel; San José Estépar, Raúl

    2018-03-01

    Introduction: The Agatston score is a well-established metric of cardiovascular disease related to clinical outcomes. It is computed from CT scans by a) measuring the volume and intensity of the atherosclerotic plaques and b) aggregating such information in an index. Objective: To generate a convolutional neural network that inputs a non-contrast chest CT scan and outputs the Agatston score associated with it directly, without a prior segmentation of Coronary Artery Calcifications (CAC). Materials and methods: We use a database of 5973 non-contrast non-ECG gated chest CT scans where the Agatston score has been manually computed. The heart of each scan is cropped automatically using an object detector. The database is split in 4973 cases for training and 1000 for testing. We train a 3D deep convolutional neural network to regress the Agatston score directly from the extracted hearts. Results: The proposed method yields a Pearson correlation coefficient of r = 0.93; p <= 0.0001 against manual reference standard in the 1000 test cases. It further stratifies correctly 72.6% of the cases with respect to standard risk groups. This compares to more complex state-of-the-art methods based on prior segmentations of the CACs, which achieve r = 0.94 in ECG-gated pulmonary CT. Conclusions: A convolutional neural network can regress the Agatston score from the image of the heart directly, without a prior segmentation of the CACs. This is a new and simpler paradigm in the Agatston score computation that yields similar results to the state-of-the-art literature.

  5. Evaluation of variation of voltage (kV) absorbed dose in chest CT scans

    International Nuclear Information System (INIS)

    Mendonca, Bruna G.A.; Mourao, Arnaldo P.

    2013-01-01

    Computed tomography (CT) is one of the most important diagnostic techniques images today. The increasing utilization of CT implies a significant increase of population exposure to ionizing radiation. Optimization of practice aims to reduce doses to patients because the image quality is directly related to the diagnosis. You can decrease the amount of dose to the patient, and maintain the quality of the image. There are several parameters that can be manipulated in a CT scan and these parameters can be used to reduce the energy deposited in the patient. Based on this, we analyzed the variation of dose deposited in the lungs, breasts and thyroid, by varying the supply voltage of the tube. Scans of the thorax were performed following the protocol of routine chest with constant and variable current for the same applied voltage. Moreover, a female phantom was used and thermoluminescent dosimeters (TLD-100), model bat, were used to record the specific organ doses. Scans were performed on a GE CT scanner, model 64 Discovery channels. Higher doses were recorded for the voltage of 120 kV with 200 mAs in the lungs (22.46 mGy) and thyroid (32.22 mGy). For scans with automatic mAs, variable between 100 and 440, this same tension contributed to the higher doses. The best examination in terms of the dose that was used with automatic 80 kV mAs, whose lungs and thyroid received lower dose. For the best breast exam was 100 kV. Since the increase in the 80 kV to 100 kV no impact so much the dose deposited in the lungs, it can be concluded that lowering the applied voltage to 100 kV resulted in a reduction in the dose absorbed by the patient. These results can contribute to optimizing scans of the chest computed tomography

  6. Automatic calibration method of voxel size for cone-beam 3D-CT scanning system

    International Nuclear Information System (INIS)

    Yang Min; Wang Xiaolong; Wei Dongbo; Liu Yipeng; Meng Fanyong; Li Xingdong; Liu Wenli

    2014-01-01

    For a cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary stage along X-ray direction. In order to realize the automatic calibration of the voxel size, a new and easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least-square fitting. Through these interpolation values, a linear equation is obtained that reflects the relationship between the voxel size and the rotary stage translation distance from its nominal zero position. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system. When the rotary stage is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy. (authors)

  7. Feasibility study of helical tomotherapy for total body or total marrow irradiation

    International Nuclear Information System (INIS)

    Hui, Susanta K.; Kapatoes, Jeff; Fowler, Jack; Henderson, Douglas; Olivera, Gustavo; Manon, Rafael R.; Gerbi, Bruce; Mackie, T. R.; Welsh, James S.

    2005-01-01

    Total body radiation (TBI) has been used for many years as a preconditioning agent before bone marrow transplantation. Many side effects still plague its use. We investigated the planning and delivery of total body irradiation (TBI) and selective total marrow irradiation (TMI) and a reduced radiation dose to sensitive structures using image-guided helical tomotherapy. To assess the feasibility of using helical tomotherapy (A) we studied variations in pitch, field width, and modulation factor on total body and total marrow helical tomotherapy treatments. We varied these parameters to provide a uniform dose along with a treatment times similar to conventional TBI (15-30 min). (B) We also investigated limited (head, chest, and pelvis) megavoltage CT (MVCT) scanning for the dimensional pretreatment setup verification rather than total body MVCT scanning to shorten the overall treatment time per treatment fraction. (C) We placed thermoluminescent detectors (TLDs) inside a Rando phantom to measure the dose at seven anatomical sites, including the lungs. A simulated TBI treatment showed homogeneous dose coverage (±10%) to the whole body. Doses to the sensitive organs were reduced by 35%-70% of the target dose. TLD measurements on Rando showed an accurate dose delivery (±7%) to the target and critical organs. In the TMI study, the dose was delivered conformally to the bone marrow only. The TBI and TMI treatment delivery time was reduced (by 50%) by increasing the field width from 2.5 to 5.0 cm in the inferior-superior direction. A limited MVCT reduced the target localization time 60% compared to whole body MVCT. MVCT image-guided helical tomotherapy offers a novel method to deliver a precise, homogeneous radiation dose to the whole body target while reducing the dose significantly to all critical organs. A judicious selection of pitch, modulation factor, and field size is required to produce a homogeneous dose distribution along with an acceptable treatment time. In

  8. Lecithin-coated gold nanoflowers (GNFs) for CT scan imaging applications and biochemical parameters; in vitro and in vivo studies.

    Science.gov (United States)

    Aziz, Farooq; Bano, Khizra; Siddique, Ahmad Hassan; Bajwa, Sadia Zafar; Nazir, Aalia; Munawar, Anam; Shaheen, Ayesha; Saeed, Madiha; Afzal, Muhammad; Iqbal, M Zubair; Wu, Aiguo; Khan, Waheed S

    2018-01-09

    We report a novel strategy for the fabrication of lecithin-coated gold nanoflowers (GNFs) via single-step design for CT imaging application. Field-emission electron microscope confirmed flowers like morphology of the as-synthesized nanostructures. Furthermore, these show absorption peak in near-infrared (NIR) region at λ max 690 nm Different concentrations of GNFs are tested as a contrast agent in CT scans at tube voltage 135 kV and tube current 350 mA. These results are compared with same amount of iodine at same CT scan parameters. The results of in vitro CT scan study show that GNFs have good contrast enhancement properties, whereas in vivo study of rabbits CT scan shows that GNFs enhance the CT image clearly at 135 kV as compared to that of iodine. Cytotoxicity was studied and blood profile show minor increase of white blood cells and haemoglobin, whereas decrease of red blood cells and platelets.

  9. Comparative evaluation of coronal images of the middle ear visualized by CT scan and polytomography

    International Nuclear Information System (INIS)

    Sugiyama, Masao; Nakai, Yoshiaki; Cho, Kansei; Tanabe, Kyoji; Inoue, Yuichi; Onoyama, Yasuto

    1982-01-01

    We retrospectively analysed the coronal images of the middle ear obtained by multidirectional tomography (polytomography) and computed tomography (CT) in 40 patients. Although CT was capable of demonstrating water density in the middle ear more clearly than polytomography and of delineating a lesion extending even outside of the petrous bone, the diagnostic capability was not much different between the two tomographic techniques. On the other hand, coronal CT scan has a disadvantage in that it usually has to be performed during hyperextension of the neck or while patients are in an uncomfortable hanging head position. We think that CT scan should be utilized only in case with a lesion extending beyond the petrous bone and/or is not well visualized by polytomography. (author)

  10. Evaluation of the image quality of chest CT scans: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Martins N, P. I.; Prata M, A., E-mail: priscillainglid@gmail.com [Centro Federal de Educacao Tecnologica de Minas Gerais, Centro de Engenharia Biomedica, Av. Amazonas 5253, 30421-169 Nova Suica, Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    Computed tomography (CT) is considered one of the most important methods of medical imaging employed nowadays, due to its non-invasiveness and the high quality of the images it is able to generate. However, the diagnostic radiation dose received by an individual over the year often exceeds the dose received on account of background radiation. Therefore, it is important to know and to control the dose distribution in the patient by varying the image acquisition parameters. The aim of this study is to evaluate the variation of the image quality of chest CT scans performed by two phantoms. In this paper, a cylindrical Polymethyl Methacrylate (PMMA) chest phantom was used and a second PMMA phantom has been developed with the same volume but an oblong shape, based on the actual dimensions of a male human thorax, in the axillary region. Ten-centimeter scans of the central area of each phantom were performed by a 16-channel Toshiba CT scanner, model Alexion. The scanning protocol employed was the radiology service protocol for chest scans. The noise survey was conducted within the image of the center slice, in five regions: one central and four peripheral areas close to the edge of the object (anterior, posterior, left and right). The recorded values showed that the oblong phantom, with a shape that is more similar to the actual human chest, has a considerably smaller noise, especially in the anterior, posterior and central regions. (Author)

  11. Evaluation of the image quality of chest CT scans: a phantom study

    International Nuclear Information System (INIS)

    Martins N, P. I.; Prata M, A.

    2016-10-01

    Computed tomography (CT) is considered one of the most important methods of medical imaging employed nowadays, due to its non-invasiveness and the high quality of the images it is able to generate. However, the diagnostic radiation dose received by an individual over the year often exceeds the dose received on account of background radiation. Therefore, it is important to know and to control the dose distribution in the patient by varying the image acquisition parameters. The aim of this study is to evaluate the variation of the image quality of chest CT scans performed by two phantoms. In this paper, a cylindrical Polymethyl Methacrylate (PMMA) chest phantom was used and a second PMMA phantom has been developed with the same volume but an oblong shape, based on the actual dimensions of a male human thorax, in the axillary region. Ten-centimeter scans of the central area of each phantom were performed by a 16-channel Toshiba CT scanner, model Alexion. The scanning protocol employed was the radiology service protocol for chest scans. The noise survey was conducted within the image of the center slice, in five regions: one central and four peripheral areas close to the edge of the object (anterior, posterior, left and right). The recorded values showed that the oblong phantom, with a shape that is more similar to the actual human chest, has a considerably smaller noise, especially in the anterior, posterior and central regions. (Author)

  12. Detection of lacunar infarction in brain CT-scans: No evidence of bias from accompanying patient information

    International Nuclear Information System (INIS)

    Bonke, B.; Knippenberg, F.C.E. van; Duivenvoorden, H.J.; Kappelle, L.J.

    1989-01-01

    Interobserver agreement in assessing brain CT-scans is, in general, high. The extent, however, to which such agreement is caused by bias through knowledge of other clinical details remains uncertain. The hypothesis that observers are somehow prejudiced before assessing ambiguous, CT-scans in this particular situation was tested. Sixteen neurologists and 16 radiologists volunteered to interpret two ambiguous brain CT-scans, with regard to the presence or absence of a lacunar infarct in the region of the internal capsule. The scans were accompanied by 'patient' information that was or was not suggestive of a stroke. These scans were camouflaged by a variety of other scans, to be assessed in the same way, to mask the purpose of the study. I was assumed that the observers, in their assessments of the scans, would somehow let their ratings of the likelihood of a lacunar infarction in or near the internal capsule be subject to the accompanying information. Results showed lower ratings produced by neurologists (i.e., less likelihood of an infarction) than by radiologists in the majority of all assessments, but no bias by the accompanying information. (orig.)

  13. Spinal CT scan, 2

    International Nuclear Information System (INIS)

    Nakagawa, Hiroshi

    1982-01-01

    Plain CT described fairly accurately the anatomy and lesions of the lumbar and sacral spines on their transverse sections. Since hernia of the intervertebral disc could be directly diagnosed by CT, indications of myelography could be restricted. Spinal-canal stenosis of the lumbar spine occurs because of various factors, and CT not only demonstrated the accurate size and morphology of bony canals, but also elucidated thickening of the joints and yellow ligament. CT was also useful for the diagnosis of tumors in the lumbar and sacral spines, visualizing the images of bone changes and soft tissues on the trasverse sections. But the diagnosis of intradural tumors required myelography and metrizamide CT. CT has become important for the diagnosis of spinal and spinal-cord diseases and for selection of the route of surgical arrival. (Chiba, N.)

  14. Impact of polychromatic x-ray sources on helical, cone-beam computed tomography and dual-energy methods

    International Nuclear Information System (INIS)

    Sidky, Emil Y; Zou Yu; Pan Xiaochuan

    2004-01-01

    Recently, there has been much work devoted to developing accurate and efficient algorithms for image reconstruction in helical, cone-beam computed tomography (CT). Little attention, however, has been directed to the effect of physical factors on helical, cone-beam CT image reconstruction. This work investigates the effect of polychromatic x-rays on image reconstruction in helical, cone-beam computed tomography. A pre-reconstruction dual-energy technique is developed to reduce beam-hardening artefacts and enhance contrast in soft tissue

  15. Measurement of mesothelioma on thoracic CT scans: A comparison of manual and computer-assisted techniques

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Oxnard, Geoffrey R.; MacMahon, Heber; Vogelzang, Nicholas J.; Kindler, Hedy L.; Kocherginsky, Masha; Starkey, Adam

    2004-01-01

    Our purpose in this study was to evaluate the variability of manual mesothelioma tumor thickness measurements in computed tomography (CT) scans and to assess the relative performance of six computerized measurement algorithms. The CT scans of 22 patients with malignant pleural mesothelioma were collected. In each scan, an initial observer identified up to three sites in each of three CT sections at which tumor thickness measurements were to be made. At each site, five observers manually measured tumor thickness through a computer interface. Three observers repeated these measurements during three separate sessions. Inter- and intra-observer variability in the manual measurement of tumor thickness was assessed. Six automated measurement algorithms were developed based on the geometric relationship between a specified measurement site and the automatically extracted lung regions. Computer-generated measurements were compared with manual measurements. The tumor thickness measurements of different observers were highly correlated (r≥0.99); however, the 95% limits of agreement for relative inter-observer difference spanned a range of 30%. Tumor thickness measurements generated by the computer algorithms also correlated highly with the average of observer measurements (r≥0.93). We have developed computerized techniques for the measurement of mesothelioma tumor thickness in CT scans. These techniques achieved varying levels of agreement with measurements made by human observers

  16. Low-dose computed tomography scans with automatic exposure control for patients of different ages undergoing cardiac PET/CT and SPECT/CT.

    Science.gov (United States)

    Yang, Ching-Ching; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin; Liu, Shu-Hsin

    2017-06-01

    This study aimed to evaluate the efficacy of automatic exposure control (AEC) in order to optimize low-dose computed tomography (CT) protocols for patients of different ages undergoing cardiac PET/CT and single-photon emission computed tomography/computed tomography (SPECT/CT). One PET/CT and one SPECT/CT were used to acquire CT images for four anthropomorphic phantoms representative of 1-year-old, 5-year-old and 10-year-old children and an adult. For the hybrid systems investigated in this study, the radiation dose and image quality of cardiac CT scans performed with AEC activated depend mainly on the selection of a predefined image quality index. Multiple linear regression methods were used to analyse image data from anthropomorphic phantom studies to investigate the effects of body size and predefined image quality index on CT radiation dose in cardiac PET/CT and SPECT/CT scans. The regression relationships have a coefficient of determination larger than 0.9, indicating a good fit to the data. According to the regression models, low-dose protocols using the AEC technique were optimized for patients of different ages. In comparison with the standard protocol with AEC activated for adult cardiac examinations used in our clinical routine practice, the optimized paediatric protocols in PET/CT allow 32.2, 63.7 and 79.2% CT dose reductions for anthropomorphic phantoms simulating 10-year-old, 5-year-old and 1-year-old children, respectively. The corresponding results for cardiac SPECT/CT are 8.4, 51.5 and 72.7%. AEC is a practical way to reduce CT radiation dose in cardiac PET/CT and SPECT/CT, but the AEC settings should be determined properly for optimal effect. Our results show that AEC does not eliminate the need for paediatric protocols and CT examinations using the AEC technique should be optimized for paediatric patients to reduce the radiation dose as low as reasonably achievable.

  17. A fully automated non-external marker 4D-CT sorting algorithm using a serial cine scanning protocol.

    Science.gov (United States)

    Carnes, Greg; Gaede, Stewart; Yu, Edward; Van Dyk, Jake; Battista, Jerry; Lee, Ting-Yim

    2009-04-07

    Current 4D-CT methods require external marker data to retrospectively sort image data and generate CT volumes. In this work we develop an automated 4D-CT sorting algorithm that performs without the aid of data collected from an external respiratory surrogate. The sorting algorithm requires an overlapping cine scan protocol. The overlapping protocol provides a spatial link between couch positions. Beginning with a starting scan position, images from the adjacent scan position (which spatial match the starting scan position) are selected by maximizing the normalized cross correlation (NCC) of the images at the overlapping slice position. The process was continued by 'daisy chaining' all couch positions using the selected images until an entire 3D volume was produced. The algorithm produced 16 phase volumes to complete a 4D-CT dataset. Additional 4D-CT datasets were also produced using external marker amplitude and phase angle sorting methods. The image quality of the volumes produced by the different methods was quantified by calculating the mean difference of the sorted overlapping slices from adjacent couch positions. The NCC sorted images showed a significant decrease in the mean difference (p < 0.01) for the five patients.

  18. Mediastinal fibrosis with pulmonary artery obstruction; diagnosis and investigation with helical CT imaging including 3-dimensional reconstructions; Pulomonalarterienstenose bei aggresiver Mediastinalfibrose; Diagnostik und 3D-Darstellung mittels helikaler CT-Untersuchung

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, M. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland); Helwig, A. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland); Habicht, J.M. [Klinik fuer Herz-Torax-Chirurgie, Universitaetskliniken Basel (Switzerland); Steinbruch, W. [Inst. fuer Diagnostische Radiologie, Kantonsspital Basel (Switzerland)

    1997-07-01

    An aggressive mediastinal fibrosis was found in a 42-year-old female, suffering from dysphagia, stabbing pain in the chest, and an unclear weight loss. In this case, the rare combination of esophageal involvement, bronchial narrowing, and pulmonary artery obstruction could easily be demonstrated with a barium study and a helical CT examination including three-dimensional reconstructions. (orig.) [Deutsch] Wir stellen den Fall einer 42jaehrigen Patientin vor, welche zur Abklaerung einer zunehmenden Dysphagie, stechender Thoraxschmerzen und eines Gewichtsverlustes hospitalisiert wurde. Mittels klinischer und radiologischer Abklaerung konnte eine aggressive Mediastinalfibrose diagnostiziert werden. Die seltene Kombination einer Oesophaguseinengung mit Pulmonalarterienstenosen sowie einer Bronchuskompression konnte nichtinvasiv mittels Oesophagogramm und helikaler CT-Untersuchung zuverlaessig und schnell dargestellt werden. (orig.)

  19. F-18-Fluorodeoxyglucose Positron Emission Tomography/CT Scanning in Diagnosing Vascular Prosthetic Graft Infection

    NARCIS (Netherlands)

    Saleem, Ben R.; Pol, Robert A.; Slart, Riemer H. J. A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2014-01-01

    Vascular prosthetic graft infection (VPGI) is a severe complication after vascular surgery. CT-scan is considered the diagnostic tool of choice in advanced VPGI. The incidence of a false-negative result using CT is relatively high, especially in the presence of low-grade infections.

  20. Computed tomographic (CT) scans in cerebral palsy (CP)

    International Nuclear Information System (INIS)

    Kolawole, T.M.; Patel, P.J.; Mahdi, A.H.

    1989-01-01

    The CT findings in 120 cerebral palsied children are analysed. The 72.5% positive findings are correlated with the clinical types, as well as the aetiological basis for the cerebral palsy. The spastic type, 83.3% of the total number of children, had the highest positive findings. The yield was increased in children with seizures (91.3%) and those in the postnatal group (90%), as well as those with birth trauma and neonatal asphyxia (94%). The findings were those of atrophy in 30.8%, hydrocephalus, in 10%, infarct in 11.6%, porencephaly in 8.3% and others. The atropic changes and their patterns are explained. Treatable lesions, such as tumour, hydrocephalus, subdural haematoma, porencephaly and hygroma were identified in 22.5% of cases. It is concluded that CT scan is definitely efficacious in the management of cerebral palsied children. (orig.)